U.S. patent number 4,839,835 [Application Number 06/717,042] was granted by the patent office on 1989-06-13 for apparatus and method responsive to the on-board measuring of the load carried by a truck body.
Invention is credited to LeRoy G. Hagenbuch.
United States Patent |
4,839,835 |
Hagenbuch |
June 13, 1989 |
**Please see images for:
( Reexamination Certificate ) ** |
Apparatus and method responsive to the on-board measuring of the
load carried by a truck body
Abstract
The invention relates to an apparatus for accurately measuring
the weight of a load carried by a truck body which is mounted on a
truck frame. The apparatus is located along an interface between
the truck frame with the load carried by the truck body and
uniformly distributes the weight of the body onto the frame along
the interface. In order to measure the weight of the load, the
apparatus includes pressure sensors which communicate the entire
weight of the load to the truck frame. The pressure sensors provide
an electrical signal proportional to the pressure exerted by the
load on the apparatus. This electrical signal is processed to
calculate the weight of the load carried in the truck body. By
providing a pressure sensing apparatus at an interface between the
load and truck frame, the weight on the load carried by the truck
body can be continually monitored without interrupting the loading,
hauling and dumping routine. A sensor processing unit responds to
the continually monitored weight data and the like to provide
hauling parameters to track the performance of the truck and to
provide a data base to a central computer from which data can be
gathered for efficiently controlling the movement of a plurality of
trucks.
Inventors: |
Hagenbuch; LeRoy G. (Peoria,
IL) |
Family
ID: |
27084738 |
Appl.
No.: |
06/717,042 |
Filed: |
April 1, 1985 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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604739 |
Apr 27, 1984 |
4630227 |
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Current U.S.
Class: |
702/174; 177/141;
701/50; 701/1; 177/136 |
Current CPC
Class: |
G07C
5/008 (20130101); G01S 5/16 (20130101); G01G
19/08 (20130101); G07C 5/085 (20130101); G08G
1/123 (20130101); G08G 1/20 (20130101); B60G
2300/026 (20130101); B60G 2600/0422 (20130101); G01S
2201/01 (20190801); B60G 2400/60 (20130101); B60G
2600/042 (20130101); B60G 2204/11 (20130101); B60G
2400/61 (20130101) |
Current International
Class: |
G07C
5/08 (20060101); G07C 5/08 (20060101); G01S
1/70 (20060101); G01S 1/70 (20060101); G01S
5/00 (20060101); G01S 5/00 (20060101); G01G
19/08 (20060101); G01G 19/08 (20060101); G01S
1/00 (20060101); G01S 1/00 (20060101); G01S
5/16 (20060101); G01S 5/16 (20060101); G08G
1/123 (20060101); G08G 1/123 (20060101); G07C
5/00 (20060101); G07C 5/00 (20060101); G01G
019/08 (); G06F 015/20 () |
Field of
Search: |
;364/424,567,568,555,558,550 ;340/52R ;73/37
;177/136,139,141,165,209 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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493628 |
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Sep 1977 |
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AU |
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0060074 |
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Sep 1982 |
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EP |
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2400447 |
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Nov 1971 |
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FR |
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2249787 |
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May 1975 |
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FR |
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84 05278 |
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Oct 1985 |
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FR |
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2562659 |
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Oct 1985 |
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FR |
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59-176133 |
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Oct 1984 |
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JP |
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WO83/04451 |
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Dec 1983 |
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WO |
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1049751 |
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Oct 1983 |
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SU |
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1215275 |
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Dec 1970 |
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GB |
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2025185 |
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Jan 1980 |
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GB |
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Primary Examiner: Gruber; Felix D.
Assistant Examiner: Mattson; Brian M.
Attorney, Agent or Firm: Leydig, Voit & Mayer
Parent Case Text
This application is a continuation-in-part application of U.S. Ser.
No. 604,739 filed 4-27-84, now U.S. Pat. No. 4,630,227.
Claims
I claim:
1. In a system of a plurality of vehicles, an apparatus on-board
each of said vehicles for acquisitioning data indicative of vehicle
operation and for relaying said data to a remote control center
where the data is processed to create control signals that are
delivered back to said apparatus for instructing a vehicle operator
regarding vehicle movement, said apparatus comprising:
(1) means mounted to said vehicle for indicating a loading of
material into a dump body of said vehicle by a loader;
(2) means mounted to said vehicle for indicating a dumping of a
load carried by said body;
(3) means mounted to said vehicle for indicating a direction of
movement by said vehicle;
a first processor means on-board said vehicle for acquiring data
generated from means (1), (2) and (3) and processing said data for
downloading to a remote control center; and
(4) means for sending said processed data to said remote control
center and for receiving control signals therefrom.
2. An apparatus as set forth in claim 1 wherein said first
processor means includes (1) memory means for storing data
indicative of a predetermined maximum weight capacity for said dump
body, (2) detection means responsive to incremental increases in a
total weight of said dump body for determining an approximate
weight of material added by a bucket of a loader, (3) comparison
means responsive to said memory, first processor and detection
means for determining if said total weight minus said predetermined
maximum weight for said dump body is a fraction of said approximate
weight of material in said bucket, and (4) display means responsive
to said comparison means for indicating a remaining weight capacity
of said truck body.
3. An apparatus as set forth in claim 2 wherein said detection
means includes:
means for detecting a monotonic increase in the total weight of
said dump body; and
means for storing said increase.
4. An apparatus as set forth in claim 2 wherein said display means
includes a display of said remaining weight capacity of said dump
body as a fraction of said approximate weight of material in said
bucket.
5. An apparatus as set forth in claim 4 wherein said display means
comprises a series of light indicators representative of an
approximate capacity of said bucket, said series of light
indicators being relatively positioned such that each light
indicator visually represents a fractional portion of said
approximate weight of material in said bucket.
6. An apparatus as set forth in claim 1 wherein said means (1)
comprises a pressure sensor assembly mounted to a frame of said
vehicle for transferring from said dump body to said frame at least
a predetermined portion of a total weight of said dump body in a
substantially uniform manner along an interface between said frame
and said dump body and said assembly is responsive to said
predetermined portion of said total weight to provide pressure data
representative of said total weight of said dump body.
7. An apparatus as set forth in claim 6 wherein said first
processor means includes means for isolating pressure data
representing pressure spikes and means for recording the occurrence
of a pressure spike, and means responsive to said recording means
for delivering data to said display means indicative of a condition
of a road over which said vehicle travels.
8. An apparatus as set forth in claim 6 wherein said pressure
sensor assembly includes a cushioning interface between said dump
body and said frame.
9. An apparatus as set forth in claim 6 wherein said dump body is
pivotally mounted to said frame by way of a hinge assembly such
that said pressure sensor assembly supports said total weight of
said dump body in a lowered position on said frame along an
interface between said frame and dump body with none of said total
weight of said dump body transferred to said frame via said hinge
assembly.
10. An apparatus as set forth in claim 9 wherein said hinge
assembly has body and frame portions and also has means for
decoupling said body and frame portions when said dump body is
moved to said lowered position such that said total weight of said
dump body is communicated to said frame through said pressure
sensor assembly.
11. An apparatus as set forth in claim 6 wherein said pressure
sensor assembly comprises at least one length of resilient tubing
positioned on a beam of said frame wherein said resilient tubing
provides an interface between said dump body and said frame for
communicating said at least predetermined portion of said total
weight of said dump body to said frame.
12. An apparatus as set forth in claim 6 including:
first transceiver means mounted to said vehicle;
said first processor means operatively coupled to said first
transceiver means and said pressure sensor assembly for receiving
said data from said pressure sensor assembly, processing said data
and transmitting said processed data by way of said first
transceiver where said processed data includes an indication of a
hauling status for said vehicle; and
said remote control center including a second processor means
having a second transceiver means for communicating with said first
transceiver means, said second processor means receiving said
processed data from said first processor means, said processed data
identifying said vehicle and said hauling status of said vehicle
derived from data from means (1), (2) and (3).
13. An apparatus as set forth in claim 12 wherein said vehicle may
be loaded by any one of a plurality of loaders;
said second processor means includes (1) first means for
calculating in response to said processed data an average load time
for each of said plurality of loaders, (2) second means responsive
to said processed data and said first means for calculating a
current load delay time for each of said plurality of said loaders,
(3) third means responsive to said second means for identifying a
one of said plurality of said loaders having a minimum load delay
(4), fourth means responsive to said third means for forming data
for transmission by said second transceiver means, said data for
transmission identifying a particular one of said plurality of
vehicles and said one of said plurality of loaders with said
minimum load delay; and
said first processor means including fifth means responsive to said
data received from said fourth means via said first transceiver for
displaying to said vehicle operator of said particular one of said
plurality of vehicles an identifier of said one of loaders.
14. An apparatus as set forth in claim 12 wherein said pressure
sensor assembly includes tubings which forms said interface between
each of said body and frame of said vehicle.
15. An apparatus as set forth in claim 12 wherein said second
processor means includes memory means for archiving said processed
data from said vehicle.
16. An apparatus as set forth in claim 12 wherein said first
processor means generates said processed data for transmission in
response to said pressure data from said pressure sensor assembly
and data generated by means (2) and (3) which are indicative of
whether said vehicle is dumping its load, beginning loading of a
new load or in transit between load and dump sites.
17. An apparatus as set forth in claim 16 wherein said means (2) is
a dump sensor and means (3) is a gear sensor and said first
processor means generates said processed data for transmission in
response to data from a plurality of sensors on-board said vehicle
including said gear and dump sensors.
18. An apparatus as set forth in claim 12 wherein said second
processor means includes memory means for archiving said processed
data in response to vehicle identification and vehicle type data
included in said processed data, thereby forming a data base.
19. An apparatus as set forth in claim 18 wherein said data base
formed by said processed data archived in said memory means is used
by said second processor means to generate said control data for
controlling the movement of said vehicle.
20. An apparatus according to claim 12 including:
said second processor means including memory means for storing a
predetermined maximum load capacity for said dump body; and
said first processor means including means for determining a weight
of said dump body from said pressure data of said pressure sensor
assembly and incorporating said weight as part of said processed
data;
said second processor means responsive to said processed data for
(1) comparing said weight with said predetermined maximum load
capacity, and (2) generating an output signal identifying said
vehicle if said weight is greater than said predetermined maximum
load capacity.
21. An apparatus as set forth in claim 20 including means
responsive to said first processor means for displaying said weight
of said dump body in response to said first processor means.
22. An apparatus as set forth in claim 20 including means in said
second processor means for accumulating a total number of times
said output signal indicating an overload of the vehicle is
generated.
23. An apparatus as set forth in claim 6 wherein said first
processor means includes:
means for storing said pressure data acquired from said pressure
sensor assembly;
means for comparing selected pressure data in said storing means
with other pressure data in said storing means to determine if said
selected pressure data are pressure spike;
means responsive to said comparing means for counting the pressure
spikes; and
means responsive to said counting means for providing an indication
of the condition of a road over which said vehicle travels.
24. An apparatus as set forth in claim 6 including:
said first processor means providing an indication of a load or
dump condition of said vehicle in response to said pressure data
from said pressure sensor assembly;
distance means for measuring the distance traveled by said vehicle
and providing said distance to said first processor means so as to
be incorporated into said processed data;
storage means responsive to said processed data for storing a
distance traveled by said vehicle between said indications of load
and dump conditions and for storing a total weight of a load hauled
by said vehicle between said indications; and
means responsive to said storage means for multiplying said
distance traveled by said total weight hauled in order to provide a
tons-miles record as part of said storage means.
25. An apparatus as set forth in claim 24 including means for
dividing said tons-miles record by a time interval between
successive indications of said load and dump conditions, thereby
providing an indication of wear experienced by said vehicle.
26. An apparatus according to claim 6 including:
memory means operatively coupled to said first processor means;
means coupled to said first processor means for entering an
identifier of said vehicle operator and for associating a portion
of said memory means with said identifier;
said first processor means responsive to said pressure data for (1)
providing said processed data which is indicative of vehicle
performance and (2) routing said processed data indicative of
vehicle performance to locations within said portion of said memory
means associated with said identifier;
detecting means responsive to said entering means for detecting
changes in said identifier; and
display means responsive to said detecting means for displaying
said processed data indicative of vehicle performance in said
portion of memory means when a change of said identifier has
occurred.
27. An apparatus as set forth in claim 6 where said vehicle
includes front and back axles and said apparatus includes means for
measuring loads carried by said front and rear axles of said
vehicle wherein said dump body is pivotally mounted to said frame
so as to pivot between raised and lowered positions, said means
comprising:
(5) means for measuring a force of said dump body on said frame and
providing data indicative of said force;
said first processor means responsive to said data from said means
(5) and said pressure sensor assembly for determining a
distribution of said weight of said dump body over said front and
rear axles of said vehicle; and
display means responsive to said first processor means for
displaying portions of said weight of said dump body carried by
said front and rear axles.
28. An apparatus as set forth in claim 27 wherein hydraulic
cylinders connected between said frame and dump body move said dump
body between said raised and lowered positions, said means (5)
sensing pressures of hydraulic fluids in said hydraulic
cylinders.
29. An apparatus as set forth in claim 27 wherein said first
processor means includes means for locating a center of gravity of
said dump body.
30. An apparatus as set forth in claim 27 wherein said first
processor means includes memory means storing predetermined tare
weights for said front and rear axles and said first processor
means including summing means for adding said portion of said
weight on each of said front and rear axles to the tare weight of
each of said front and rear axles in order to find a gross weight
for each of said front and rear axles.
31. An apparatus as set forth in claim 6, including means for
pivoting said dump body between raised and lowered positions on
said dump body,
said pressure sensor assembly including a plurality of sensor
elements and providing an interface between said frame and dump
body when said dump body is in a lowered position,
said plurality of sensor elements provides an indication of the
total weight of said dump body and an indication of fore-and-aft
weight distribution as well as side-to-side weight distribution of
the load carried by the dump body; and
said first processor means having means responsive to said
plurality of sensor elements of said pressure sensor assembly for
detecting an imbalance of said weight carried by said dump body and
signaling said vehicle operator in response thereto.
32. An apparatus as set forth in claim 6 wherein said body is
pivotally mounted to said frame for movement between lowered and
raised positions and said apparatus includes a distance sensor for
providing data to said first processor means indicative of truck
movement, said first processor means including means responsive to
said distance sensor and to said pressure sensor assembly for
providing an output signal when said vehicle moves without said
dump body in said lowered position.
33. An apparatus as set forth in claim 6 wherein said dump body is
pivotable between raised and lowered positions and wherein said
first processor means includes (1) memory means for storing a tare
weight of said dump body, (2) means responsive to the lowering of
said dump body onto said pressure sensor assembly for comparing
said total weight of said dump body with said tare weight in said
memory means, and (3) means for indicating said dump body is not
fully empty when said total weight of said dump body is greater
than said tare weight of said dump body plus a predetermined
constant.
34. An apparatus as set forth in claim 1 wherein said means (1)
comprises a bi-state switch positioned in a recess of a bed of said
dump body so as to detect a presence of material carried in said
dump body.
35. An apparatus for processing data derived from a weight of a
load carried by a body of a truck, said apparatus comprising:
a truck frame including a hinge assembly for pivotally supporting
said truck body between raised and lowered positions;
a pressure sensor assembly mounted to said frame for supporting an
entire weight of said body in its lowered position and providing
pressure data representative of said entire weight of said truck
body;
a processor means for receiving said pressure data and detecting a
change in said entire weight of said truck body and formulating
data indicative of truck condition in response to said pressure
data and its change;
a distance sensor for providing distance data to said processor
means indicative of truck movement; and
said processor means including first means responsive to said
pressure data for detecting said truck body raised off said
pressure sensor assembly and second means responsive to said first
means and said distance data for providing an output signal when
said truck moves with said body raised off said pressure sensor
assembly.
36. An apparatus for processing data derived from a weight of a
load carried by a body of a truck, said apparatus comprising:
a truck frame including a hinge assembly for pivotally supporting
said truck body between raised and lowered positions;
a pressure sensor assembly mounted to said frame for supporting a
weight of said body in its lowered position and providing pressure
data representative of said weight of said truck body;
a processor means for receiving said pressure data and detecting a
change in said weight of said truck body and formulating data
indicative of such condition in response to said pressure data and
its change; and
said processor means including (1) memory means for storing a
predetermined tare weight of said truck body, (2) means responsive
to a lowering of said truck body onto said pressure sensor assembly
after a load carried by said body has been dumped for comparing
said weight of said truck body with said tare weight in said
memory, and (3) means for indicating said body is not fully empty
when said weight of said body is greater than said tare weight of
said body plus a predetermined constant.
37. An apparatus for determining a remaining weight of capacity of
a body carried on a truck frame which is loaded with a material by
a bucket of a loader and for indicating when a weight of said
material in a full average bucket is more than said remaining
weight capacity of said body, said apparatus comprising in
combination:
a truck frame including a hinge assembly;
a truck body pivotally mounted to said truck frame at said hinge
assembly, said truck body being pivotally movable on said frame
between lowered and raised positions;
a pressure sensor assembly mounted to said frame for supporting a
weight of said body in its lowered position and providing pressure
data representative of a weight of said truck body;
a processor means for receiving said pressure data and determining
said weight of said truck body, said processor means including;
(1) memory means for storing data indicative of a predetermined
maximum weight capacity for said truck body, (2) detection means
responsive to incremental increases in said weight of said truck
body for approximating a weight of said material added by said
bucket, (3) comparison means responsive to said weight, said
predetermined maximum weight capacity and said weight of said
material added by said bucket for determining said remaining weight
capacity of said truck body, and (4) display means responsive to
said comparison means for indicating said remaining weight capacity
of said truck body.
38. An apparatus as set forth in claim 37 wherein said detection
means includes;
first means for detecting an increase in said weight of said truck
body; and
second means for storing said increase.
39. An apparatus as set forth in claim 37 wherein said processor
means includes means for isolating pressure data representing
pressure spikes and means for recording an occurrence of a pressure
spike, and means responsive to said recording means for delivering
data to said display means indicative of a road condition.
40. An apparatus as set forth in claim 37 wherein said display
means includes a display of a remaining weight capacity of said
truck body as a percentage of said weight of said material carried
by said bucket.
41. An apparatus as set forth in claim 40 wherein said display
means comprises a series of light indicators representative of a
volume capacity of said bucket, said light indicators being
relatively positioned such that each light represents a fractional
portion of said volume capacity of said bucket.
42. An apparatus as set forth in claim 37 wherein said pressure
sensor assembly is also a cushioning interface between said truck
body and said truck frame.
43. An apparatus as set forth in claim 37 wherein said pressure
sensor assembly includes a support means mounted on said truck
frame, said support means directly supporting said truck body on
said truck frame when said truck body is in a lowered position,
said support means supporting said truck body in its lowered
position in such a manner as to support an entire amount of said
weight of said body along an interface between said truck frame and
body with none of said weight of said body transferred to said
truck frame via said hinge assembly.
44. An apparatus as set forth in claim 37 wherein said hinge
assembly has body and frame portions and also has means for
decoupling said body and frame portions when said truck body is
moved to said lowered position such that an entire amount of said
weight of said truck body is communicated to said truck frame
through said pressure sensor assembly.
45. An apparatus as set forth in claim 37 wherein said pressure
sensor assembly comprises at least one length of resilient tubing
positioned on a beam of said truck frame wherein said resilient
tubing provides an interface between said truck body and said truck
frame for communicating an entire amount of said weight of said
body to said frame when said body is in said lowered position.
46. A system for minimizing a hauling time for each of a plurality
of trucks between load and dump sites, said system comprising:
a plurality of on-board weighing devices each mounted on one of
said plurality of trucks for providing signals indicative of a
truck's operation;
a plurality of processor means each mounted to one of said
plurality of trucks and each processor means responsive to a one of
said plurality of on-board weighing devices for receiving said
signals from said one of said plurality of on-board weighing
devices and processing said signals to provide data indicative of a
hauling status;
a plurality of first transceiver means each mounted to one of said
plurality of trucks for receiving said data indicative of a hauling
status from said one of said plurality of processor means and
transmitting said hauling status data in association with
additional data that identifies said one of said plurality of
trucks; and
a remote processing center including second transceiver means for
receiving said hauling status and truck identifying data from said
one of said plurality of first transceiver means, said remote
processing center generating a historical data base, containing
said data indicative of a hauling status and indexed by said
identifying data.
47. A system as set forth in claim 46 wherein said on-board
weighing device includes a pressure sensor assembly mounted on the
frame of the truck and supporting the body of the truck uniformly
along an interface between the truck body and frame.
48. A system as set forth in claim 46 wherein a plurality of
loaders are provided at said load sites for loading said plurality
of trucks; and
said remote processing center includes (1) first means for
calculating in response to at least said data base an average load
time for each of said plurality of loaders, (2) second means
responsive to at least said data base and said first means for
calculating a current load delay time for each of said plurality of
loaders, (3) third means responsive to said second means for
identifying one of said plurality of loaders with a minimum load
delay time, (4) fourth means responsive to said third means for
forming control data for transmission by said second transceiver
means, said control data identifying a particular one of said
plurality of trucks and a particular one of said plurality of
loaders with said minimum load delay time; and
each of said plurality of processor means mounted to said plurality
of trucks includes fifth means responsive to said control data
received by said first transceiver for displaying for said
particular one of said plurality of loaders identified by said
control data.
49. A system as set forth in claim 46 wherein said pressure sensor
assembly includes tubings which forms the interface between each of
said body and frame of said trucks.
50. A system as set forth in claim 46 wherein said data base
comprises a memory means responsive to said remote processing
center for archiving said hauling status and identifying data
transmitted from said plurality of trucks.
51. A system as set forth in claim 46 wherein said processor means
generates hauling status data for transmission in response to said
signals from said pressure sensor assembly which are indicative of
whether a particular one of said plurality of trucks in dumping its
load, beginning a loading or in transit between load and dump
sites.
52. A system as set forth in claim 46 wherein said remote
processing center includes memory means for archiving said hauling
status and identifying data from each of said plurality of
processors in groups such that said data base is firstly
identifiable with individual ones of said plurality of trucks and
secondly identifiable with types of trucks comprising said
plurality of trucks.
53. A system as set forth in claim 52 wherein said remote
processing center is responsive to the said data base formed by
said hauling status and identifying data archieved in said memory
means to generate control data for controlling the movement of said
plurality of trucks by causing said second transceiver to transmit
said control data to said plurality of first transceivers.
54. A method for detecting and recording a degree of road roughness
for a truck having a body supported on a frame,said method
comprising the steps of:
periodically calculating a value of a force derived from a weight
of said truck body on said truck frame;
storing said value so as to accumulate a plurality of stored
values;
periodically comparing a selected one of said plurality of stored
values with other of said plurality of stored values to determine
if said one of said plurality of stored values is a spike wherein
said spike is a stored value that is greater than said other of
said plurality of stored values by a predetermined amount;
accumulating said spikes and providing a total count of said
spikes; and
deriving from said total count of said spikes an indication of the
degree of road roughness and displaying said indication.
55. A method as set forth in claim 54 wherein said force derived
from said weight of said truck body on said truck frame is
calculated with said truck body fully lowered onto said truck
frame.
56. A method as set forth in claim 54 wherein said force derived
from said weight of said truck body on said truck frame is provided
by a pressure sensor interfaced between the truck body and frane to
communicate a predetermined portion of said weight of said truck
body to said truck frame.
57. A system for measuring a degree of tire use by a vehicle which
hauls material in a dump body pivotally mounted to a frame of said
vehicle, said apparatus comprising;
distance means for measuring a distance traveled by said vehicle
and providing distance data;
an on-board weighing device responsible to a weight of a load of
said material hauled by said vehicle for providing (1) weight data
and (2) data indicative of a beginning and an ending of a haul
cycle;
storage means responsive to said distance means and said on-board
weighing device for accumulating said distance and weight data;
and
processor means responsive to said weight and distance data for (1)
time marking at least a portion of said distance and weight data so
as to identify an elapsed time of said haul cycle, (2) determining
a total distance and a weight of said material for said haul cycle,
(3) multiplying said total distance and said weight of said
material for said haul cycle to provide a sum, (4) dividing said
sum by said elapsed time, and (5) displaying a value resulting from
said multiplying means.
58. An apparatus as set forth in claim 57 wherein said on-board
weighing device includes a pressure sensor assembly mounted on said
frame of said vehicle which fully supports said weight of said load
when said body is pivoted into a lowered position.
59. An apparatus as set forth in claim 58 wherein said body is
pivotally mounted to said frame by way of a hinge assembly such
that said body is fully supported by said pressure sensor assembly
when said truck body is in said lowered position.
60. An apparatus for use in connection with an off-road, heavy-duty
truck wherein said apparatus records vital statistics of said truck
in connection with an identifier entered into said apparatus by a
truck operator, said apparatus comprising:
a processor means including memory means;
means coupled to said processor means for entering said identifier
and associating a first portion of said memory means with said
identifier;
measuring means for providing signals indicative of a hauling
status of said truck to said processor means;
said processor means responsive to said measuring means and said
entering and associating means for (1) receiving said signals, (2)
providing data indicative of truck performance in response to said
signals and (3) routing said data to locations within said first
portion of said memory means;
detecting means responsive to a change of said identifier to cause
said entering and associating means to associate a second portion
of said memory means with a new identifier resulting from said
change of said identifier; and
said processor means responding to said associating of said second
portion of said memory means with said new identifier by routing
said data to locations within said second portion of said memory
means.
61. An apparatus as set forth in claim 60 wherein said truck has a
body pivotably mounted on a truck frame, said measuring means
including:
a pressure sensor assembly supporting an entire weight of said body
on said truck frame when said body is in a fully lowered position
and said pressure sensor assembly providing pressure data
representative of said weight of said truck body; and
said memory means including data indicative of a predetermined
maximum weight for said truck body.
62. A system for identifying an overload condition in an off-road,
heavy-duty truck having a body mounted to a truck frame by a hinge
assembly for movement between lowered and raised positions, said
apparatus comprising, in combination:
a sensor assembly mounted on said truck frame and supporting a
predetermined portion of a weight of said truck body on said truck
frame when said truck body is in said lowered position, said sensor
assembly responding to said weight of said body to provide a signal
indicative of said weight of said body;
a means for transferring said signal to a remote, off-board
processor means;
said remote off-board processor means responsive to said signal and
including memory means for storing a predetermined maximum weight
capacity for said truck body; and
said remote off-board processor means responsive to said signal
from said sensor assembly indicative of said weight for comparing
said weight with said predetermined maximum weight capacity, and
for generating an output signal if said weight indicated by said
signal is greater than said predetermined maximum weight
capacity.
63. A system as set forth in claim 62 including means for
displaying said weight of said truck body.
64. A system as set forth in claim 62 including means in said
remote off-board processor means for accumulating a total number of
times said output signal is generated.
65. An apparatus for measuring and manipulating various hauling and
loading parameters for an off-road, heavy duty truck having a body,
a frame and front and rear axles, said apparatus comprising:
a first weighing device on said truck for measuring a first force
of said truck body on said truck frame and providing data
representative of said first force;
a second weighing device on said truck for measuring a second force
of said truck body on said truck frame and providing data
indicative of said second force;
a processor means responsive to said first and second weighing
devices for determining a fraction of a total weight of said truck
body over said front axle and a fraction of said total weight of
said truck body over said rear axle of said truck; and
display means responsive to said processor means for displaying
said fractions of said total weight supported by said front and
rear axles.
66. An apparatus as set forth in claim 65 wherein said truck frame
includes a hinge assembly and said truck body is pivotally mounted
to said truck frame at said hinge assembly such that said truck
body is pivotable between raised and lowered positions, said first
weighing device supporting the entire weight of said truck body
when said truck body is in its lowered position.
67. An apparatus as set forth in claim 66 wherein hydraulic
cylinders connected between said truck frame and body move said
truck body between said raised and lowered positions, said second
weighing device sensing a pressure of hydraulic fluid filling said
hydraulic cylinder.
68. An apparatus for measuring and manipulating various hauling and
loading parameters for an off-road, heavy duty truck having a body,
a frame and front and rear axles, said apparatus comprising in
combination:
hinge assemblies pivotally joining said truck frame and body;
a sensor assembly mounted on said truck frame and including a
plurality of sensor elements, said sensor assembly supporting a
predetermined portion of a weight of said truck body when said
truck body is in a lowered position on said truck frame;
said sensor assembly providing an interface between said truck
frame and body when said body is in said lowered position such that
said plurality of sensor elements provides an indication of said
weight of said truck body and an indication of fore-and-aft and
side-to-side distribution of said weight of said truck body;
and
processor means responsive to said sensor assembly for detecting an
imbalance of said weight carried by said truck body and signalling
a truck operator in response thereto.
69. A stationary platform scale for placement on an approximately
level ground surface, said scale comprising, in combination:
a first planar plate;
a plurality of flexible tubing laid on said first planar plate with
each tubing having first and second ends;
a second planar plate positioned to rest atop said plurality of
flexible tubing, said second planar plate extending to fully cover
said plurality of flexible tubing;
a plurality of pressure sensors each secured to one of said first
or second ends of each of said plurality of flexible tubing for
providing pressure data indicative of a weight present on said
second planar plate;
said second planar plate having a lower surface for direct contact
with each of said plurality of flexible tubing wherein said lower
surface includes a calibration plate to ensure a known surface area
of contact between said plurality of flexible tubing and said
second planar plate; and
means for gathering all the data from said plurality of pressure
sensors and determining a weight present on said second planar
plate.
70. A stationary platform scale as set forth in claim 69 including
stablization means coupling said first and second planar plates to
retard movement parallel to the planes of said plates while
simultaneously allowing the plates to move relative to one another
in a direction normal to the planes of said plates.
71. In a system for controlling a routing of a fleet of vehicles
composed of distinct groups to a plurality of possible locations, a
method for monitoring and commanding vehicle movement comprising
the steps of:
sensing a weight and a change in said weight of a load carried by
each vehicle and formulating data representative of said weight and
said change in weight;
transferring said data to a central location;
cataloging at said central location said data from each
vehicle;
selecting one of said distinct groups of vehicles;
combining said data from said one of said distinct groups of
vehicles to provide collective data indicative of group
performance; and
analyzing said cataloged and collective data to provide commands
for transfer to selected vehicles in said fleet of vehicles.
72. In a system for controlling a routing of a fleet of
load-carrying vehicles composed of distinct groups to a plurality
of possible locations, an apparatus for monitoring and commanding
vehicle movement comprising, in combination:
first means on-board each of said vehicles in said fleet of
vehicles for sensing a change in a load carried by said vehicle and
forming data representative of said change;
second means on-board each of said vehicles for transmitting said
data;
a central computer for receiving said data from each of said
vehicles in said fleet of vehicles and (1) cataloging said data to
provide averages for each of said vehicles, (2) analyzing said
averages from each of said vehicles and (3) forming control data in
response to said analysis that includes identification data
identifying at least one vehicle in said fleet of vehicles; and
transmitting means coupled to said central computer for
transmitting said control data to a vehicle identified by said
identification data.
73. In a system as set forth in claim 72 including repeater
transmitters strategically located along routes of said fleet of
vehicles and each of said repeater transmitters receiving said data
from vehicles in its vicinity and retransmitting said data to said
central computer such that said retransmitted data identifies said
each repeater transmitter, thereby providing an approximate
location of each vehicle in said fleet of vehicles.
74. In a system as set forth in claim 72 wherein said control data
includes data designating sites for loading and dumping loads
carried by said fleet of load-carrying vehicles and each vehicle in
said fleet includes a display means responsive to said control data
for displaying said designated sites to a vehicle operator.
75. In a system as set forth in claim 72 wherein each vehicle in
said fleet of vehicles is loaded with material by a loader and said
data from said first on-board means provides an indication of the
operation of said loader;
said central computer including means responsive to said data for
providing a quantitative indication of an efficiency of said
loader.
76. In a system as set forth in claim 72 wherein each vehicle in
said fleet of vehicles includes a pivotal body mounted on a frame
for movement between raised and lowered positions and said first
on-board means includes a pressure sensor assembly mounted to said
frame for supporting a weight of said body in said lowered
position.
77. In a system as set forth in claim 76 wherein an interface is
formed where said pivotal body meets said frame, said pressure
sensor assembly is mounted on said frame such that said pressure
sensor assembly extends continuously along said interface when said
body is moved to said lowered position.
78. In a system as set forth in claim 72 wherein said first
on-board means includes means for detecting an increase in said
load carried by said vehicle.
79. In a system for controlling a routing of a fleet of trucks
composed of distinct groups to a plurality of possible locations
and including a central computer for receiving data from said
trucks and issuing commands to said trucks, said trucks having a
dump body pivotally mounted to a frame, an apparatus on-board each
of said trucks comprising, in combination:
a pressure sensor assembly mounted to each truck in said fleet of
trucks for providing pressure data indicative of a weight of said
dump body;
a processor means on-board each of said trucks for receiving said
pressure data and detecting a change in a weight of said body, and
providing output data indicative of a truck operating condition;
and
transmitter means on-board each of said trucks for receiving said
output data from said processor means and transmitting said output
data to said central computer for further processing.
80. In the system set forth in claim 79, said central computer
including means for receiving said output data and formulating a
data base for each truck and each group of trucks, said central
computer also including means responsive to said data base for
providing control data to a second transmitter means operatively
coupled to said central computer.
81. In the system set forth in claim 80 a receiver means on-board
each of said trucks for receiving said control data and delivering
it to said processor means.
82. In the system set forth in claim 81, said processor means
including means responsive to said control data to provide display
data to an on-board display means for use by a truck operator.
83. An apparatus for measuring a weight of a load carried by a body
of a truck, said apparatus comprising, in combination:
a truck body and a truck frame;
means for coupling said body to said frame to inhibit side-to-side
or fore-to-aft movement of said body with respect to said frame but
allowing limited non-rotating vertical movement; and
a pressure sensor assembly supporting a predetermined portion of a
weight of said body along an interface between said body and frame
such that a weight of said body is transferred to said frame
uniformly along said interface.
84. An apparatus as set forth in claim 83 wherein said pressure
sensor assembly includes a signal output indicative of pressure and
said apparatus includes a processor means for receiving said signal
output.
85. An apparatus as set forth in claim 84 wherein said processor
means includes means for detecting a change in said weight of said
truck body and formulating data indicative of said truck condition
in response to said pressure data.
86. A system for automatically measuring a weight of a vehicle body
and automatically transferring a measurement of said weight to a
remote stationary site, said system comprising, in combination:
a vehicle frame for supporting said body;
a pressure sensor assembly mounted on said vehicle frame and
positioned along an interface between said vehicle body and frame
for supporting a predetermined portion of said weight of said
vehicle body such that said assembly distributes said predetermined
portion of said weight of said vehicle body in a substantially
uniform manner along said interface, said assembly providing at
least one output signal indicative of a pressure at said interface
between said body and frame;
means remote from said vehicle for receiving said at least one
output signal and formulating an indication of said weight of said
body; and
coupling means joining said pressure sensor assembly and said
remote means for automatically transferring said at least one
output signal from said assembly to said remote site.
87. A system according to claim 86 wherein said at least one output
signal from said pressure sensor assembly is fluid under pressure
and said remote means is a pressure responsive device for providing
a visual indication indicative of said weight of said body and said
coupling means is a conduit for communicating said fluid under
pressure from said assembly to said pressure responsive device
remote from said vehicle.
88. A system according to claim 86 wherein said at least one output
signal from said pressure sensor assembly is an electrical signal
and said remote means is a circuit responsive to said electrical
signal when received via said coupling means.
89. A system according to claim 88 wherein said pressure sensor
assembly comprises liquid-filled tubing.
90. In a system utilizing pressurized tubing, an apparatus for
terminating an end of said tubing and for insuring the termination
is leak-proof under high pressures, said apparatus comprising, in
combination:
an end clamp located at said end of said tubing and comprising
first, second and third portions;
said third portion of said end clamp located inside said tubing
while said first and second portions fit over an outside surface of
said tubing and opose one another so as to sandwich said tubing and
third portion between said first and second portions;
means for joining said first, second and third portions of said
clamp with said tubing so as to totally seal the end of said
tubing; and
a collar surrounding said tubing at an area proximate said end of
said tubing but rearward of said end clamp, said collar having a
central bore for receiving said tubing and restraining said tubing
from changing its cross-sectional shape in an area of said tubing
under and adjacent to said collar.
91. In a system for monitoring hauling parameters of a vehicle with
a dump body that pivots between raised and lowered pivotal
positions, an on-board apparatus comprising, in combination:
a sensor mounted on said body and responsive to the pivoting of
said body for providing an output signal indicative of said raised
or lowered positions of said body, said sensor being totally
encapsulated in a housing in order to prevent ambient conditions
from reducing the responsiveness of said sensor;
a processor for receiving said output signal from said sensor and
responding to said output signals in a predetermined manner;
and
means communicating said output signal from said sensor to said
processor wherein said means includes an output port in said
housing which maintains said sensor in isolation from an ambient
environment.
92. The on-board apparatus as set forth in claim 91 wherein said
sensor is a mercury switch.
93. In a system for controlling a routing of each vehicle in a
fleet of material-hauling vehicles to one of a plurality of
possible load or dump locations, an apparatus for monitoring and
commanding vehicle movement comprising, in combination:
means on-board each of said vehicles for providing an indication of
a beginning of a loading of material into said vehicle and a
dumping of said material from said vehicle and, in response to said
indication, forming data indicative of said loading or dumping;
first transceiver means on-board each of said vehicles for
transmitting said data;
a central computer having a second transceiver means for receiving
said data from each of said vehicles and having a processor and a
memory for formulating from said data a data base from which
control data is derived, said central computer including means for
transmitting said control data to said vehicles, said control data
including data identifying a particular vehicle and a particular
one of said plurality of possible load or dump locations; and
said first transceiver means receiving said control data and said
on-board sensing means responding to said control data to visually
indicate said particular one of said plurality of possible load or
dump destinations on an on-board display means.
94. An apparatus on-board a vehicle, being one of a plurality of
similar vehicles, for acquisitioning data indicative of vehicle
operation and for accumulating said data, said apparatus
comprising:
first means mounted to said vehicle for providing data indicative
of a loading of material into a dump body of said vehicle and a
dumping of said material by said dump body;
second means mounted to said vehicle for providing data indicative
of a movement of said vehicle;
a first processor means on-board said vehicle for acquiring said
data from said first and second means and organizing said data to
provide information regarding performance of said vehicle; and
a storage means for receiving said data from said first processor
means and storing said data as organized by said first processor
means.
Description
TECHNICAL FIELD
The invention generally relates to the measuring of the load of a
vehicle and, more particularly, to the measuring and acquisition of
data indicative of loading conditions for a hauling vehicle.
BACKGROUND
Often off-road trucks are subjected during their routine use to
weight loads which differ greatly because of different material
density and/or the ability of some material to more tightly pack
when loaded into the truck body. As a result, truck bodies which
are always filled to their full volume capacity may carry weight
loads which exceed the weight capacity of the truck. Repeated
occurrences of overloading result in the premature deterioration of
the structural integrity of the truck, thus requiring repair or
replacement of parts before anticipated. In order to avoid the
damage caused by overloading, the truck body can be filled to a
volume which assures the truck is not overloaded even for the most
dense material. Although underloading may prevent the premature
deterioration of the structural integrity of the truck, it
sacrifices the truck's load-hauling efficiency. Therefore, an
off-road truck which is expensive to operate becomes even more
expensive to operate when it is underloaded. Accordingly, there is
a need to precisely measure the load carried by an off-road truck.
This need has stimulated the development of on-board weighing
devices that monitor and measure the truck's load.
Of course, in order to measure the on-board weight of a load
carried by a truck, the truck must necessarily incorporate load
sensors into its frame and/or body. In a dump-body truck, the body
is movable on the truck's frame between lowered and raised
positions. To provide for this movement, the body is usually
attached to the frame only by a pair of hinge assemblies and a pair
of hydraulic cylinders. In one common construction of a dump-body
truck, when the truck body is in its lowered position, its entire
weight is communicated to the truck frame along a cushioned
interface between the truck's frame and body. In this lowered
position of the truck body, the hinge assemblies and hydraulic
cylinders do not support the weight of the truck body and,
therefore, they do not transfer any of the body's weight to the
truck frame. By freeing the hinge assemblies and the hydraulic
cylinders from the weight of the lowered truck body, the amount of
stress on these areas is reduced and, accordingly, their useful
life is extended.
Traditionally, in order to provide an on-board weighing device for
this type of a dump-body truck, load sensors are incorporated into
the hinge assemblies and the hydraulic cylinders. Accordingly, in
order to measure the load, the truck body must be lifted from its
lowered position by the hydraulic cylinders so that the weight of
the load is transferred to the frame through the cylinders and the
hinge assemblies. Although the accuracy of the load measurements
obtained from load sensors associated with the hydraulic cylinders
and the hinge assemblies is satisfactory, the structural integrity
of the truck may be degraded by modifications of the hinge
assemblies and hydraulic cylinders required to incorporate the load
sensors which cause concentration of the load on the frame.
Moreover, the impact of falling material onto the bed of the truck
is especially severe for the frame of the truck when the body is
lifted slightly from its lowered position.
More important than the structural disadvantage of on-board
weighing devices which incorporate load sensors in the truck's
hinge assemblies and hydraulic cylinders is the disadvantage of
requiring the truck's body to be lifted off the frame in order to
obtain a weight reading. Because this requirement consumes valuable
time otherwise available for loading, hauling, and unloading and
because of the concentration of the load on the frame, the truck
operator is discouraged from weighing the truck load; it is faster
to approximate the load. Since the on-board weighing device
interferes with an efficient and smooth hauling operation, there is
a tendency to not use the weighing device. Therefore, the
advantages of an on-board weighing devices in dump-body trucks have
not been fully realized. Also, the requirement of lifting the truck
body off the frame in order to obtain a weight measurement prevents
continuous or periodic monitoring of the body's weight.
In order to continuously monitor and measure the load carried by a
dump-body truck, it is known to use pressure gauges or similar type
load sensors in the truck's suspension. Usually, in these types of
weighing devices, the fluid pressure within a hydraulic suspension
cylinder is sensed. Because of the relatively short stroke of the
cylinder and the relatively large amount of frictional resistance
to the cylinder's movement (the front cylinders normally also serve
as the front axle spindles), the pressure reading is not a
satisfactorily accurate indication of the truck's weight. In
addition, the modification of the truck's suspension to include
load sensors opens the possibility of dangerously degrading the
suspension system.
SUMMARY OF THE INVENTION
It is the general object of the invention to provide an apparatus
and method for accurately measuring loading and hauling parameters
based on the weight of material carried by a truck body. In this
connection, it is a object of the invention to reliably measure and
record loading and hauling parameters of the truck body in order to
increase the efficiency of loading and hauling and also to provide
a permanent record of truck use and the conditions under which it
operated.
It is an important object of the invention to provide an apparatus
and method for measuring and indicating locating and hauling
parameters of the truck body in order to provide an archive
indicative of the type and degrees of use the truck has
experienced.
It is another object of the invention to extend the usable life of
a dump-body truck by using loading and hauling parameters to
prevent the unnecessary deterioration of the structural integrity
of the truck resulting from weight overloading.
It is a further object of the invention to eliminate the
inefficient hauling of loads by a dump-body truck which results
from the under-utilization of the full weight capacity of the
truck.
Other objects and advantages of the invention will be apparent from
the following detailed description and the accompanying
drawings.
Briefly, in accordance with the invention, an on-board weighing
device is provided for a dump-body vehicle which continuously
monitors the weight of the body while it is in its lowered position
on the frame of the vehicle. In its lowered position, the body
rests on the on-board weighing device such that the device forms an
interface between the body and frame of the vehicle. A sensor
processing unit mounted on the vehicle is responsive to signals
from the on-board weighing device which are indicative of the
weight of the body. From the load signals of the on-board weighing
device, the sensor processing unit forms a data base from which the
vehicle's hauling performance is measured. In addition, load
signals from the on-board weighing device are processed by the
sensor processing unit and the resulting data is transmitted from
each vehicle to a central processor wherein a second data base is
formed. From this second data base, the central processor transmits
control signals to selected vehicles in order to control the
movement of the vehicles between load and dump sites.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevated perspective view of a dump-body truck with
the truck body in a raised or dump position so as to expose the
on-board weighing device according to the preferred embodiment of
the invention;
FIG. 2 is an enlarged elevated perspective view of the dump-body
truck in FIG. 1 that more clearly shows the on-board weighing
device according to the preferred embodiment of the invention;
FIG. 2a is an exploded perspective view of a truck having a
stationary body and supported on a frame incorporating the on-board
weighing device according to the invention;
FIG. 2b is a systems diagram of an on-board system according to the
invention for monitoring, storing and analyzing truck parameters
which includes the on-board weighing device as well as other sensor
inputs;
FIG. 3 is a cross-sectional view of one of the truck body hinge
assemblies joining the truck body and frame, taken along the line
3--3 in FIG. 2 and showing three alternative pivot pin assemblies
offered by various truck manufacturers;
FIG. 3a is a sectional view of the truck hinge assembly taken along
the line 3a--3a in FIG. 3 and showing a suggested modification to
one of the pivot pin assemblies of FIG. 3 in order to make the
hinge assembly "free-floating";
FIG. 4 is a side view of the preferred embodiment of the on-board
weighing device according to the invention, taken substantially
along the line 4--4 in FIG. 2;
FIG. 5 is a front view of the on-board weighing device according to
a first alternative embodiment of the invention, taken along the
line 5--5 in FIG. 4;
FIG. 5a is a front view of a second alternative embodiment for the
on-board weighing device according to the invention, taken along
the line 5--5 in FIG. 4;
FIG. 6 is a front view of the preferred embodiment for the on-board
weighing device according to the invention, taken along the line
5--5 in FIG. 4;
FIG. 7 is a cross-sectional view of the preferred embodiment for
the on-board weighing device according to the invention, taken
along the line 7--7 in FIG. 4;
FIG. 7a is an enlarged partial side view of the on-board weighing
device taken along the line 7a--7a in FIG. 7 showing details of the
means for securing the device to the truck frame;
FIG. 8 is a plan view of a clamping subassembly of the on-board
weighing device;
FIG. 8a is an exploded end view of a clamp portion of the clamping
subassembly, taken along the line 8a--8a in FIG. 8;
FIG. 9 is a cross-sectional view of the clamping subassembly in
FIG. 8, taken along the line 9--9 and showing a side view of a
collar portion of the subassembly;
FIG. 10 is a side view taken along the line 4--4 in FIG. 2 showing
a first alternative embodiment of the on-board weighing device
according to the invention;
FIG. 11 is an end view of the first alternative embodiment of the
on-board weighing device, taken along the line 11--11 in FIG.
10;
FIG. 12 is a side view taken along the line 4--4 in FIG. 2 showing
a second alternative embodiment of the on-board weighing device
according to the invention;
FIG. 13a is a side view of a heavy duty, off-road truck
illustrating the relative dimensions of the truck used by the
on-board weighing device of the invention to measure front and rear
axial loads;
FIG. 13b is a side view of the heavy duty, off-road truck of FIG.
13a with the truck body slightly raised by the hoist cylinders in
order for the on-board weighing device to complete a determination
of front and rear axial loads;
FIGS. 14a and 14b are side views of a scraper vehicle in its raised
and lowered positions, respectively, illustrating the relative
dimensions used to estimate front and rear axial loads;
FIGS. 14c and 14d are partially side views of the scraper vehicle
in FIGS. 14a and b, respectively, illustrating the relative
positions of the vehicle's hoist cylinder and associated
mechanisms;
FIGS. 15a and 15b are plan and side views, respectively, for a
platform scale incorporating the on-board weighing device of the
invention;
FIG. 16 is a block diagram of the electronic system which receives
signals from the on-board weighing device according to the
invention;
FIG. 16a is a schematic diagram of the temporary memory used in
connection with the electronic system of FIG. 16;
FIG. 17a is a plan view of a mechanical processing system for
receiving signals from the on-board weighing device in lieu of the
electronic system of FIG. 16;
FIG. 17b is a cross-sectional view of the mechanical processing
system taken along the lines 17b--17b in FIG. 17a;
FIG. 17c is a perspective view of the piston subassembly of the
mechanical processing system;
FIGS. 18a-f, h-k, m, p and r are flowchart diagrams for the
software utilized in connection with the electronic system of FIG.
14;
FIGS. 19a and 19b are schematic diagrams illustrating a truck
distribution system utilizing the weight data received from the
on-board weighing device of the invention;
FIG. 19c is a enlarged, partial sectional view of the truck body
showing an alternative embodiment for sensing the presence of a
load for use in connection with the truck distribution system of
FIGS. 19a and 19b; and
FIGS. 20a and 20b are flowchart diagrams for the software of the
central computer and truck, respectively, utilized in connection
with the truck distribution system of FIGS. 19a and 19b.
While the invention will be described in connection with a
preferred embodiment and certain alternative embodiments, it will
be understood that it is not intended to limit the invention to
those particular embodiments. On the contrary, it is intended to
cover all alternatives and equivalents as may be included within
the spirit and scope of the invention as defined by the appended
claims.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning to the drawings, and referring first to FIG. 1, an
exemplary off-road truck 11 includes a truck body 13 which is
hinged to the truck frame 15 at hinge assemblies 17. By controlling
the extension of telescoping hydraulic cylinders 19 and 21, the
truck body 13 is pivoted between a fully inclined or dump position
and a lowered or rest position. One end of each hydraulic cylinder
19 and 21 is fastened to a hinge assembly located on the bottom of
the truck body 13. The opposing end of each cylinder 19 and 21 is
fastened to an articulation on the truck frame 15. Structurally,
the truck body 13 consists of steel panels 23, which form the shape
of the body, and beams 25 which provide the body's structural
framework. Since other dump-body trucks may also use the on-board
weighing device of this invention, the truck in FIG. 1 is intended
as an exemplary truck frame and truck body utilized in connection
with the invention.
Often, off-road trucks, such as the one shown in FIG. 1, are very
large. For instance, it is not uncommon for the truck's tire
diameter to be as great as the height of an average man.
Accordingly, the tremendous size of these trucks makes them
expensive to operate and repair. Since these trucks represent both
a large capital investment and a large operating expense,
preventing both overloading of the truck body and under-utilization
of the truck's load capacity (i.e., underloading) are important
considerations in insuring the truck is operated in the most
profitable manner. In particular, if the truck is overloaded it
will tend to have a shorter usable life because of the excessive
wear caused by the overloading. On the other hand, if the truck is
underloaded, the truck must be operated over a longer period of
time, thereby consuming more fuel and wearing the truck's parts to
a greater degree. Therefore, the ability to accurately measure the
truck's load is important to the efficient operation of large
off-road trucks. Also, since these off-road, heavy duty trucks are
extremely expensive to operate, loading and hauling parameters
indicative of truck performance can be of great economic value by
using the parameters to discover areas of the performance which may
be improved.
Typically, a shovel or front-end loader is used to fill the truck
body. With a front-end loader, material is loaded into the truck
body 13 by a bucket located at the end of an arm of the loader
wherein the arm controls the movement of the bucket. Typically, the
truck body has a weight and volume capacity such that a plurality
of loaded buckets must dump material into the truck body 13. Even
though the operator of the front-end loader is at an elevated level
when operating the loader, he or she may not be in a position to
see over the edge of the truck body to determine the level of
loading. Consequently, it is difficult to exactly control the
amount of material loaded into the truck body. Moreover, the
density of the material loaded into the truck body often varies
over a significant range; therefore, even if it is possible to
accurately determine a certain level of loading, a particular level
is only a reliable indication of a weight limit when the material
is homogeneous and its density is known.
As most clearly shown in FIG. 2 the truck frame 15 is composed of
two parallel beams 26 and 27 connected by transverse beams (not
shown) to form a support surface for the truck body 13 over the
rear axle of the truck. In order to provide a pivot axis for the
truck body 13, each of the hinge assemblies 17 integrally connects
one end of each of the parallel beams 26 and 27 to one of beams 28
and 29 on the underside of the truck body. In its lowered position,
the beams 28 and 29 of the truck body 13 mate with the beams 26 and
27 of the truck frame 15. As will be more fully explained
hereinafter, when the truck body 13 is in its lowered position, the
entire weight of the truck body and its load is transferred to the
truck frame 15 by way of the interface between the beams 26 and 27
of the frame and the beams 28 and 29 of the body. As mentioned
above, trucks are different design than that shown as an exemplary
embodiment may use the invention. Some truck designs have beams 26
and 27 which are angled with respect to the ground. These types of
trucks may also be equipped with the invention if suitable
precautions are taken against slippage of the apparatus on the
beams and to ensure proper calibration.
Each of the hinge assemblies 17 includes first and second
complementary hinge members 30 and 31 which are secured to the
frame 15 and body 13, respectively, and interconnected by a pivot
pin 32. The hydraulic cylinders 19 and 21 and the truck body 13 are
interconnected by hinge assemblies 33. (Only one of the hinge
assemblies 33 can be seen in the view of FIGS. 1 and 2). Hoist pins
35 interconnect the complimentary hinge members 37 and 39 of the
hinge assemblies 33. Although, as the cylinders extend, the hinge
assemblies 33 accommodate the relative repositioning between the
hydraulic cylinders 19 and 21 and the truck body 13, articulating
assemblies 41 (only one is shown in FIGS. 1 and 2), which connect
the cylinders to the truck frame 15, allow a similar relative
repositioning between the hydraulic cylinders and the truck frame
15.
Ordinarily, cushioning suport materials such as rubber pads (not
shown) are added along the length of the two parallel beams 26 and
27 of the truck frame 15 so when the truck body 13 is in its
lowered position the material provides a cushioned interface
between the beams 28 and 29 of the truck body and the beams 26 and
27 of the truck frame. In order to evenly distribute the weight of
the truck body 13 along the length of the frame 15 and thereby
provide the best possible weight distribution for the frame, the
cushioning support material is characterized by a thickness
dimension which, as explained hereinafter, cooperates with the
hinge assemblies 17 when the truck body is moved to its lowered
position. The cooperation of the cushioning support material and
the hinge assemblies 17 frees the assemblies from supporting any of
the truck body's weight when the body is in its lowered
position.
Referring to FIG. 4, in accordance with the invention, the
cushioning support materials mounted by the manufacturer on the
parallel beams 26 and 27 of the truck frame 15 are replaced by
lengths of fluid-filled tubings 47 that are laid along the lengths
of the parallel beams to provide, when combined with pressure
sensors, an on-board weighing device which accurately measures the
weight of the truck body 13 while it is in its lowered position.
Each of the tubings 47 is capped by an inverted U-shaped metallic
shield 49 to protect the tubing at its interface with the truck
body 13. The inverted U-shaped shields which protect the tubing are
free to move vertically on the parallel beams 26 and 27. As
illustratedin FIG. 4, each of the fluid-filled tubings 47 is
divided into fore and aft sections which may either be created by
clamping the center of one long tubing or providing two separate
sections of tubing. At the ends of each of the fluid-filled tubings
47 are pressure sensors 51a-d which measure the liquid pressure
within the tubing (which may be remote mounted).
Because the on-board weighing device offers a reliable indication
of the weight of a dump body while the body is in its lowered or
resting position, weight data may be accurately and continuously
monitored and processed. Applicant believes such an ability was
previously unavailable for dump-body trucks. Based on this ability,
the on-board weighing device provides vehicle information features
which, to the best of applicant's knowledge, were previously
unavailable. Limited only by the sensitivity of the sensors used as
the pressure sensors 51, the on-board weighing device may provide a
highly accurate indication (e.g., 0.25% or 0.5% error) of the load
carried by an off-road, heavy-duty truck. An example of a
particular pressure transducer which may be used for the pressure
sensors 51 is the Heise Series 620 Pressure Transducer,
manufactured by the Instruments Division of Dresser Industries,
Newton, Conn. Another example of a pressure sensor suitable for use
in connection with the invention is the AMETEK LVDT pressure
transducer, manufactured by Ametek of Sellersville, Pa. The
following paragraphs characterize the general and particular
aspects of the invention which are described in detail in later
sections of this description.
Referring to FIG. 2a, a fixed body 13' fitted to the frame 15 of
the truck 11 may also utilize the on-board weighing system of the
invention. The particular means for coupling the frame 15 to the
body 13' in FIG. 2a allows the full weight of the body to rest upon
the tubings 47. The coupling means, pins 160 supported by cross
members 162 of the frame 15 and cooperating bores 164 in cross
members 166, prevent fore-and-aft or side-to-side movement of the
body relative to the frame while, at the same time, allowing free
vertical movement of the body 13'. In order to prevent the body 13'
from accidentally freeing itself from the body by bouncing high off
the frame, a cotter pin or similar retainer means 168 is secured at
the top of the pins 160 in order to limit the vertical movement of
the body. As indicated by FIG. 2a, the stationary truck body 13'
may in style be a dump-body, (the leftmost portion of the body
13'), a flatbed body (the rightmost portion of the body 13'), or it
may be other known body types which suitably function as stationary
bodies.
Referring to FIG. 2b, in addition, the on-board weighing device
includes a processor means 101 responsive to signals from the
sensor 51a-d. By providing an on-board processing means, the raw
pressure data from the on-board weighing device can be monitored
and converted to useful weight information for the real-time
control of the truck by the operator. As a complement to the
pressure data, the on-board system illustrated in FIG. 2b includes
other input data source with provide raw data to the processor
means 101. As will be explained more fully hereinafter, useful
operator information is supplied via outputs from the processor
means 101 in response to the pressure data from the on-board
weighing device and its complementary sensors.
The complementary systems in ths system include, but are not
limited to, a hoist cylinder pressure gauge 139, a distance sensor
138, a forward-neutral-reverse (F-N-R) switch 135 and a dump switch
137. A keypad 122 is used by the operator to request data and to
enter an operator number which identifies himself to the system.
Examples of other possible complementary input devices are fuel
consumption flow meters and slope transducers for detecting the
pitch or grade of the road.
Various on-board outputs controlled by the processor means 101
provide the truck operator with indications of truck operating
conditions in response to the raw data from the on-board weighing
device and complementary sensors. Specifically, a printer 119
provides a hard copy output for analysis by the truck operator or
management personnel. An audio output 196 alerts the operator to
situations requiring immediate attention. Similarly, display 197
tells the operator of a load imbalance which requires correction.
In order to provide the operator with non-permanent data
information, such as current weight, a digital dispaly 117 is
provided. Stacked lights 140 are preferably mounted on the side of
the truck in order to give the operator of the loader equipment an
idea of the remaining capacity in the truck. Finally, a transceiver
150 is provided in order to download accumulated data to a remote
site for construction of historical files. The cooperation and
interaction of the foregoing inputs and outputs in FIG. 2b will be
set forth in detail hereinafter. Before proceeding to the specific
description of this cooperation and interaction, a summarized
overview will be presented. Following this, descriptions of
subassemblies for the on-board weighing device will be described in
detail and alternative embodiments of the device will be briefly
mentioned before proceeding to a detailed discussion of data
manipulation.
In accordance with the invention, an apparatus for processing data
derived from the weight of the load carried by the body of a truck
includes a processor means 101 for receiving data from the pressure
sensors 51 and, in response thereto, detecting a change in the
weight of the truck body and formulating data indicative of truck
condition in response to changes in pressure data from the pressure
sensors. Pressure data and indications of changes in the data are
used by the processing means 101 to establish a data base from
which various truck parameters may be monitored either by the
processor means or by a remote stationary processor (not shown)
radio linked to the on-board processor by way of transceiver
150.
In accordance with one particular aspect of the invention, the
processor means 101 cooperates with the on-board weighing device
for determining the average weight of the material carried by a
bucket of a front-end loader and displaying information to the
truck or loader operator on the stacked display 140 indicative of
whether another full bucket can be loaded into the truck body 13
without overloading the truck. If another full bucket cannot be
loaded into the truck, a display indicates to the truck or loader
operator the fraction of a loaded bucket which can be safely added
to the truck body. By providing the foregoing means and functions,
the truck 11 can be safely and regularly loaded to its maximum
hauling weight without risking damage to the truck by exceeding its
weight limit.
In connection with the foregoing, the processor means includes
means for detecting an overload condition by comparing the actual
weight of the truck body with a predetermined maximum weight. If
the weight of the truck body exceeds the predetermined maximum
weight, an overload condition is recorded and indicated to the
truck operator on digital display 117.
In accordance with another particular aspect of the invention, the
on-board weighing device cooperates with a pressure sensor 139 in
the hydraulic line of the hydraulic cylinders 19 and/or 21 to
provide data to the processor means 101 for establishing the
relative weight distribution of the truck body over the front and
rear axles. The processor means 101 processes the pressure readings
from the on-board weighing device and pressure readings from the
sensor 139 of the hydraulic cylinders 19 and/or 21 in order to
provide the truck operator with accurate values for front and rear
axle loads.
In accordance with yet another particular aspect of the invention,
the on-board weighing device includes means for providing a
plurality of pressure readings fore and aft of the truck body 13,
and, in addition, side to side of the truck body. The processor
means 101 compares the fore and aft or side-to-side distributions
of load in order to warn the truck operator at display 197 or audio
output 196 of imbalanced conditions which may harm the truck.
In accordance with still another particular aspect of the
invention, the on-board weighing device cooperates with distance
sensor 138 to provide data to the processor means 101 in order to
give an indication of tire wear in units of tons.miles/hour which
is commonly used in the heavy duty truck industry as an indication
of the loading capability of the tire. This unit of measurement has
been established as a maximum tire loading and is indicative of
tire wear for tires of heavy duty, off-road trucks. Tire wear is
important since, for many truck users, the highest hourly operating
cost after the operator himself is the cost of tire replacement.
For each haul cycle segment (i.e., load to dump site or vice
versa), the processor means (1) reads the pressure reading from the
on-board weighing device which corresponds to the weight of the
body 13 and adds to that weight the known weight of the truck, (2)
reads the hauling distance of the truck 11 from the distance sensor
138 and (3) reads the hauling time of the truck. This collected
data is downloaded to a remote central station for calculation of
ton.mile per hour for display to management personnel. In a related
aspect of the invention, the processor means is responsive to the
pressure data from the on-board weighing device and the data from
the distance sensor to provide an indication of truck movement when
the body is not fully lowered on the truck frame and also to
provide an indication of a "haul-back condition", i.e., a partial
load remaining in the body after a dump has been completed.
In accordance with another particular aspect of the invention, the
processor means 101 includes means for processing and storing
hauling data derived from the on-board weighing device in order to
catalog and record important parameters of truck and operator
performance. By identifying each operator and/or down-time status,
(e.g., operator on break, truck in shop for maintenance) by unique
identification numbers, data generated while a particular operator
is controlling the truck or while the truck is in a particular
down-time status may be recorded and cataloged by the processor
means. Operator data is stored in a memory means until they are
called for by the operator through keypad 122. When called, the
processor means organizes the data into a displayed/printed
summary.
In accordance with another particular aspect of the invention, the
processor means 101 includes means for determining the degree of
roughness of the road traveled by the truck 11 by identifying
pressure spikes measured by the on-board weighing device. Because
excessively rough roads can affect the efficiency of hauling and,
more importantly, substantially damage the trucks, the degree of
roughness of the roads traveled by the truck 11 is an important
parameter.
In accordance with another particular aspect of the invention, a
central computer is provided having a signal link with each of the
processors means 101 on-board the off-road, heavy duty trucks. Data
transmitted from each of the processor means by way of transceiver
150 to the central computer is processed by it and instruction data
is returned to each processor means. Specifically, a data base is
developed by the central computer from data downloaded from the
processor means 101 of all the trucks whereby the central computer
monitors and controls truck movement. For example, conclusions
reached from the downloaded data, are used by the central computer
to route the trucks to load and dump sites most efficiently and/or
to control the type of load delivered to a particular dump
site.
Finally, in accordance with another particular aspect of the
invention, the foregoing features provided by the processor means
in response to data from the on-board weighing device and accessory
devices mounted on the truck are also realized for an off-road
scraper vehicle or for a stationary platform scale. For a scraper
vehicle, pressure data indicative of material load is provided to
an on-board processor means for generating a data base from which
total load and load distribution can be estimated. For a platform
scale, the on-board weighing device is modified to provide the
essential pressure data required by the processor means to
establish a data base from which total load can be determined.
Turning now to specific subassemblies of the on-board weighing
device and also several alternative embodiments of the device, FIG.
3 illustrates three alternative embodiments in one cross-sectional
view in order to show common hinge assembly configurations offered
by various truck manufacturers. Referring specifically to the
center embodiment in FIG. 3, in order to free the hinge assemblies
17 from the weight of the truck's load when the truck body is moved
to its lowered position, oversized bores 43 of the hinge members 30
(the bores receive the body pivot pins 32) allow the hinge members
31 to lift the pivot pins 32 into a position which disengages the
hinge member 30 from the hinge members 31. By providing the
cushioning support material with a thickness dimension greater than
the distance from the lowermost portion of the beams 28, 29 to the
beams 26 and 27 when the beams are parallel, the engagement of the
truck body with the cushioning support material causes the pivot
pins 32 securely held by the bores 44 in the hinge members 31, to
be lifted off the lower surfaces of the bores. Also, as is well
known in the art, when the truck body 13 is moved to its lowered
position and the telescoping cylinders 19 and 21 are fully
collapsed, the hydraulic cylinders are released to a float
position.
Accordingly, when the truck body 13 is moved to its lowered
position, the entire weight of the truck body is transferred from
the hinge assemblies 17 and hydraulic cylinders 19 and 21 to the
body-frame interface provided by the cushioning support material
between the beams 26, 27 and the beams 28, 29, wherein the latter
are in parallel with the former. It will be appreciated that this
cushioning support material is provided by the truck manufacturer
in order to (1) cushion the mating surfaces between the beams 28,
29 of the truck body 13 and the beams 26, 27 of the truck frame 15,
(2) provide a surface which lifts the truck's weight off the hinge
assemblies 17 when the body is moved to its lowered position,
thereby evenly distributing the truck's load along the length of
the frame 15 and (3) allow for variations in parallelness between
beams 26, 27 and beams 28, 29. As illustrated by the righthand
embodiment of the hinge assembly in FIG. 3, the oversized bores 43'
of the hinge members 30 may be lined with a rubber-like material 45
and a sheathing 45a in order to dampen any excessive movement of
the pivot pins 32 in the oversized bore and protect the wall of the
bore from damage.
Because the thickness of the assembly comprising the fluid-filled
tubings 47 and the metallic shields 49 is equal to the thickness of
the cushioning material that they replace, the pivot pins 32 are
lifted off the lowermost portion of the bores 43 when the truck
body is moved to its lowered position. Accordingly, when the truck
body 13 is lowered onto the parallel beams 26 and 27 of the truck
frame, the entire weight of the truck body 13 and its load is
transferred to the truck frame 15 by way of the interface provided
by the fluid-filled tubings 47. As a result of the fluid-filled
tubings 47 supporting the entire weight of the truck body 13 in its
lowered position, an increase in liquid pressure sensed by the
pressure sensors 51 which accurately represents the total weight of
the truck body. Not only do the fluid-filled tubings 47 provide a
mechanism for measuring the total weight of the load carried by the
truck body, they also provide the cushioned support between the
truck body 13 and the truck frame 15 previously provided by the
truck manufacturer's cushioning support material.
Generally, the tubings 47 should be composed of material that is
resistant to penetration by oil (oil is the most preferred liquid
for filling the tubings). More importantly, the tubings 47 must not
be susceptible to permanent deformation from the weight of the
truck body 13. In particular, the tubings 47 should not include any
type of braided wire that might permanently deform under external
pressure. An example of a tubing suitable for use in connection
with the invention is the JAFIB fire hose manufactured by the
Jaffrey Fire Protection Company, Inc. of New Hampshire. For any
particular choice of hose, it must be wear and abrasion resistant.
A modified fire hose may be used; an example of a preferred
modified fire hose is a three-ply urethane fire hose (i.e.,
concentric layers of urethane, fiber and urethane) with an added
inner lining of hose fiber with the fiber's inner diameter covered
with a sealing material such as rubber.
It will be appreciated by those familar with off-road trucks that
some manufacturers provide a cushioning support material between
the truck body 13 and truck frame 15, but they do not provide a
means to free the hinge assemblies 17 from supporting a portion of
the weight of the truck body when in a lowered position. Such a
hinge assembly is shown by the leftmost embodiment in FIG. 3
wherein the pivot pin 32 fits snugly within the bore 43". In
accordance with the invention, these types of trucks may be
modified to allow all the weight of the body to be supported along
the body-frame interface by machining small crescent profiles off
the tops of the pivot pins 32 such that the profile of the pins is
egg shaped. As illustrated by the modified pin 32 in FIG. 3a, this
modification allows the hinge members 30 and 31 to disengage when
the truck body is lowered onto the tubings 47, thereby enabling the
pressure sensors 51 to measure the pressure from the full weight of
the truck body.
In order to calibrate the fluid-filled tubings 47 which support the
truck body 13 in its lowered position over the truck frame 15, a
liquid (e.g., oil) of relatively low viscosity is pumped into the
tubings while the empty truck body is resting on the tubings, i.e.,
in its lowered position. Relatively low viscosity is chosen in
order to ensure proper flow during winter temperatures. The pumping
of the liquid is stopped when the beams 28 and 29 of the truck body
13 are parallel to the beams 26 and 27 of the frame 15. At this
point there is still a slight amount of contact between the pvot
pins 32 and the lower portions of the bores 43 in the hinge members
30. Therefore, there is still a slight amount of body weight
supported on the frame 15 through the hinge assemblies 17. In order
to lift the pivot pins 32 off the hinge members 30, additional
liquid is pumped into the tubings 47 until the pivot pins 32 are
visually lifted off the lowermost portions of the bores 43.
Although there is some downward vertical movement of the inverted
U-shaped metallic shields 49 as the truck body 13 is loaded, the
movement is not sufficient to cause the pivot pins 32 to re-engage
the bores 43 of the hinge members 30.
At each pressure sensor 51a-d associated with the fluid-filled
tubings 47, the liquid pressure is converted to an electrical
potential which is delivered to electrical circuitry, discussed
hereinafter, to calculate a weight measurement. Referring to FIG.
4, each of the fluid-filled tubings 47 is preferably cut at its
central area in order to provide two separate fluid-filled
chambers. By cutting the tubings 47, each pressure sensor 51a-d at
an end of a tubing 47 supplies the electronic circuitry with an
independent pressure reading. By dividing each tubing 47 into two
chambers, the corresponding four pressure readings can be
manipulated to provide an indication of the weight distribution of
the load, e.g., too much weight fore, aft or side to side as will
be discussed in greater detail hereinafter.
In alternative configurations of the tubings, each tube can be a
unitary piece such as schematically shown in FIG. 5 or it may
consist of a plurality of tubings of smaller cross-section as shown
in FIG. 5a (these smaller tubes may be within a larger tube).
Referring to FIG. 6, in order to provide an easily ascertainable
amount of contact area between the fluid-filled tubings 47 and the
shields 49, a contact plate 60 is secured to the bottom of the
channel formed by the shields in the preferred embodiment of the
invention. The tubings 47 are filled with fluid so as to provide a
contact surface along the entire cross-sectional length of the
plate 60. Also, the tubings 47 are free from contacting the side
walls of the shields 49. By the tubings 47 only contacting the
bottom surface of plate 60, the weight can be accurately
determined, i.e., pressure.times.area=weight.
Turning to FIG. 7, a more detailed cross-section of the apparatus
comprising the on-board weighing device is shown. A subassembly,
comprised of welded portions 61a, 61b and 61c illustrated in FIG.
7, is provided for securing the on-board weighing device to each of
the beams 26 and 27. The subassembly fits over each of the beams
(beam 27 is shown in FIG. 7). In order to secure the subassembly on
the beam 27, a flat plate 62 is butted against the lower surface of
the beam 27 and fastened to the portions 61a and 61b of the
subassembly by way of nuts and bolts 63a and 63b, respectively.
Referring to FIG. 7a in conjunction with FIG. 7, outrigger pairs
64a and 64b are secured to the shield 49. Fitted between the pairs
of outriggers 64a and 64b are bolt assemblies 190a and 190b,
respectively, which are secured to side portions 61a and 61b,
respectively. Because of rods 191a and 191b extending between the
outrigger pairs 64a and 64b, respectively, the shield 49 is
restrained from accidently coming free from its position over the
tubings 47. Upward movement of the shield 49 and the integrally
attached outrigger pairs 64a and 64b will cause the rods 191a and
191b to engage the bolt assemblies 190a and 190b, respectively. At
the same time, the shield is able to move downwardly in response to
the weight of the truck body.
The subassembly 61a-c is fitted over the top of the beam 27 such
that the planar horizontal surface portion 61c provides the
supporting surface for the tubing 47. The horizontal surface is
welded to the two wing portions 61a and 61b in order to allow the
first portion 61c to fit over the top of beam 27 in much the same
manner as a saddle on a horse's back. The shield 49 and plate 60
are fitted over the tubing 47 in the same manner as discussed in
connection with FIG. 6. In order to provide horizontal stability
for the tubing 47 and the shield 49, vertical guides 65a and 65b
are integrally attached to opposing ends of the planar horizontal
surface of portion 61c. The guides 65a and 65b cooperate with the
side walls of the shield 49 to inhibit any side-to-side movement of
the tubing 47. The dashed line indicated as 27' is included to
indicate the beam 27 may be a square beam instead of the I-beam
illustrated.
Referring to FIGS. 8, 8a and 9, an end clamp 68 at the end of each
tubing 47 assures that the interface of the tubing 47 and one of
the sensors 51a-d remains intact throughout the life of the
on-board weighing device. As illustrated in FIG. 9, a collar 70
retains the tubinng 47 in a cavity formed by joining top and bottom
portions 70a and 70b, respectively, of the collar 70. End clamp 68
has similar top and bottom portions 68a and b, respectively, and
also a center portion 68c as shown in the exploded view in FIG. 8a.
The end clamp portion 68c includes a centrally-tapped hole for
receiving a threaded extension of one of the sensors 51a-d which
join to secure and seal the end of the tubing 47. Because of the
pressure exerted on the tubings 47 when they support the weight of
the truck body 13, there is a substantial force acting at the ends
of the tubings. Each end of the tubings 47 must be terminated in a
manner which assures the tubing will not rupture. The metallic
collar 70 restrains the end of the tubing 47 where it joins with
the clamp 68 and one of the sensors 51a-d in order to prevent a
rupture at the tubing-sensor interface provided by the end clamp
68. To further assure the tubing 47 remains sealed at the end
clamps 68, very strong, high quality adhesives of commercial grade
are added between the tubing 47 and the end clamp portions 68a,b
and c in order to form a strong bond at the clamp-tubing interface.
The adhesive is also added between the inner walls of the tubing at
its end in order to aid in its sealing. As indicated by FIG. 8,
bolts secure the respective upper and lower sections of both the
end clamp 68 and the collar 70.
Referring to FIG. 10, in an alternative embodiment of the on-board
weighing device according to the invention, the cushioning support
material 52 remains on the parallel beams 26 and 27 to provide a
cushioned interface between the truck frame 15 and the truck body
13, but each of the beams 28 and 29 of the truck body 13 is
modified so that they include the on-board weighing device as
described in connection with FIGS. 1-4. The two pieces illustrated
in FIG. 10, sections 29a and 29b of the beam 29, are joined by a
plurality of bolts 57 extending along the length of the two-piece
beam. The two pieces of beam 28 (not shown) are constructed and
joined in the same manner. By providing a two-piece beam
construction with tubing 47 or load cells (not shown) sandwiched
between the two pieces, the total weight of the truck's load can be
accurately measured in accordance with the invention, ie., without
lifting the truck body 13 off the truck frame 15.
Although this alternative embodiment requires the modification of
the truck body 13, there is no required modification of the truck
frame 15 or the cushioning material, and therefore, there is no
possibility of a structural weakening of the load's support surface
(i.e., the truck frame). Moreover, since the modification of the
truck body merely makes two pieces from what formerly was one
piece, there is also little danger of reducing the structural
integrity of the truck body. Specifically, the weight of the load
is continuously distributed through the tubings 47 along the length
of the interface between the two pieces of the truck body, thereby
assuring that there are no high stress areas which might be
susceptible to fracturing under heavy loads.
In some vehicle manufacturer's truck designs, when the truck body
13 is in its lowered position the weight of the truck body is
supported at the back end of the body by way of the hinge
assemblies and at the front of the body by way of a relatively
small body-frame interface area. When the body is in its lowered
position, the body area intermediate these two support areas is
suspended over the frame as shown in FIG. 12. For these types of
truck bodies there is no cushioning support material along the
length of the parallel beams of the frame. When the truck body is
in its lowered position, the interface area 55 supports the beam 29
of the truck body 13 on the beam 27 of the frame 15 at the end of
the body opposite the hinge assemblies 17, thereby preventing the
body from being cantilevered. For these types of truck
constructions, an on-board weighing device according to the
invention is provided by positioning load sensors 57 and 59 at the
interface area 55 and at the hinge assemblies 17, respectively,
since these are the two points that support the truck body over the
truck frame 15 when the body is in its lowered position. A
particular example of a load cell suitable for use in connection
with the embodiment of FIG. 10 is the fatigue-resistant load cell
(models 3116 or 3152) manufactured by Lebow Assoc., Inc. of Troy,
Mich.
As an alternative to positioning the load cell 59 in FIG. 12 at the
hinge assembly 17, the load cell may be located between the
interface between beams 27 and 29 (indicated as 59' in FIG. 12) if
the hinge assemblies 17 are modified, as needed, to provide a
"floating" hinge pin as shown in FIG. 3a. With a floating hinge
pin, the weight of the truck body will be fully supported along the
interface between the beams 27 and 29 and, thereby, the load cells
57 and 59' will provide an accurate indication of body weight. As a
further alternative, a shortened version of the on-board weighing
device of FIGS. 1-9 may replace the load sensor 57 while
maintaining the load sensor 59.
Referring to FIG. 13a, the off-road, heavy duty truck includes a
pressure sensor added to the hydraulic line connected to the
hydraulic cylinders 19 and 21; by providing a pressure measurement
from the hydraulic line of the hydraulic cylinder 21, in addition
to the pressure measurement provided by the on-board weighing
device, a determination can be made of the weight distribution of
the load over the front and rear axles 71a and 73a, respectively,
by summing moments about the hinge assemblies 17. By summing the
moments about the hinge assembly 17, the location of the center of
gravity of the load carried by the truck body 13 can be determined.
By determining the location of the center of gravity of the load
carried by the truck body 13, the relative distribution of the
total weight of the load over the front and rear axles can be
determined.
In order to determine the axle loads, the truck 11 may be
schematically represented as a horizontal line 74 in FIGS. 13a and
13b which passes through both front and rear axles. In practice,
the vertical height of the load's center of gravity is not
important; therefore, the moment equation about the hinge
assemblies 17 (the vertical height of the hinge assemblies is also
ignored) gives the one dimension of the location of the center of
gravity of the load which is important in determining the axle
loads, i.e., its location relative to the front and rear axles.
In order to determine the location of the center of gravity of the
load along the length of the truck 11 as shown in FIGS. 13a and
13b, the truck body must be lifted slightly from its lowered
position as shown by the distance h in FIG. 13b in order that the
hydraulic cylinders 19 and 21 provide a pressure reading indicative
of the force required to pivot the truck body 13 about the hinge
assemblies 17. By providing the horizontal line 74 with a
calibration in predetermined units such as inches or feet, the
horizontal placement of the center of gravity relative to the front
and rear axles can be determined.
Since the hydraulic cylinders 19 and 21 are positioned at an angle
.PHI. with respect to a vertical axis perpendicular to the
horizontal line 74 in FIGS. 13a and 13b, the pressure reading from
the pressure transducer associated with hydraulic cylinders 19 and
21 must be multiplied by cylinder area (to provide a force
measurement) and by the cosine of the angle .PHI. in order to
determine the vertical force at the cylinder hinge assembly 33.
Although the angle .PHI. changes with the extension of the
hydraulic cylinders 19 and 21, a predetermined value for the angle
.PHI. can be stored in the memory of the process associated with
the on-board weighing device as discussed hereinafter since the
truck body 13 need be raised only a slight amount (shown as the
distance h in FIG. 13b) such that the angle .PHI. can be treated as
a constant for purposes of determining the relative axle loads.
Once the vertical force at the cylinder hinge assembly 33 is
determined, the equation for the moments about the body hinge
assembly 17 and along the horizontal axis has only one unknown,
i.e., the horizontal distance of the center of gravity from the
body hinge assembly 17. The following equation expresses the
relationship of the moments about the body hinge assembly 17:
wherein "Total Weight" is the most recent pressure reading from the
on-board weighing device representing the load carried on the truck
frame 15 multiplied by a predetermined constant to provide a force
measurement, and C/G is the location of the center of gravity of
the load projected onto the horizontal line 74; "Cylinder Weight"
is the pressure from the pressure transducer in the hydraulic line
to hydraulic cylinders 19 and 21 multiplied by the area of the
cylinders; the angle .PHI. is the angle formed by the longitudinal
axis 75 of the cylinder 21 and a vertical axis 76 in FIGS. 13a and
13b; and (y+z) is the distance on the horizontal line 74 between
the body hinge assembly 17 and the cylinder hinge assembly 33.
Solving for the location of the center of gravity, the equation is
as follows: ##EQU1##
With the horizontal position of the center of gravity located, the
load on each axle can be determined by solving for the axle weights
using the sum of the moment arms about the axle and along the
horizontal line 74. For the front axle, the sum of the moment arms
about the rear axle provides an equation for solving for the load
on the front axle. The equation for the moment arms about the rear
axle is as follows:
Solving for the weight on the front axle, the equation becomes,
##EQU2##
To find the load on the rear axle, the moment arms are taken about
the front axle as set forth in the following equation: ##EQU3## The
weight of the frame of the truck 11 bearing on the front and rear
axles (i.e., the tare weight) can be added to the calculated
weights in order to provide total weights bearing on the front and
rear axles. To find the tare weights for the front and rear axles,
the truck 11 may simply be weighed one axle at a time on a platform
scale as in FIGS. 15a-b. In measuring this tare weight, the truck
body 13 may be removed from the truck 11 or the weight of the body
attributable to the front and rear axles may be subtracted from the
weight recorded by the platform scale (FIGS. 15a-b). The resulting
weight measurement may be stored in the memory of the electrical
circuitry associated with the on-board weighing device as discussed
hereinafter.
Since the horizontal distances represented by the values for w, x,
y and z are known and since the pressure in hydraulic cylinders 19
and 21 is known when the truck body 13 is lifted slightly off the
frame 15, the center of gravity for the load (weighed by the
on-board weighing device) can be determined from equation two. Once
the center of gravity for the load is determined, the distribution
of the load between the front and rear axles, 71a and 73a
respectively, can be easily determined from equations four and
six.
Determination of axle loads can be made in off-road vehicles of
other types using a similar approach as disclosed in connection
with the off-road truck of FIGS. 13a-b. For example, a scraper
vehicle 81, shown in its raised and lowered positions in FIGS. 14a
and 14b, respectively, utilizes a pressure sensor in connection
with its hoist cylinder 82 to estimate the front and rear axle
loads of the scraper. A scraper vehicle loads ground material into
its body by lowering an open end of the body into contact with the
ground. As the scraper moves forward, the ground material is swept
into the body of the scraper by way of the lowered opening. In
other words, the bottom edge of the body scrapes the ground
surface, hence the name "scraper".
The mechanism which lifts and lowers the body 83 of the scraper 81
are most clearly shown in FIGS. 14c-d. In its lifted or raised
position, the hoist cylinders 82 (only one is shown) holds the body
83 off the ground. In order to prevent material from falling out of
the body 83, a gate assembly 84 is provided to close the opening in
the body 83 when it is in its lifted or raised position. Control of
the gate assembly is provided by a linkage 85 in a well-known
manner.
Referring back to FIG. 14a, longitudinal dimensions v, w, x, y and
z of the scraper 81 are used to calculate an approximate axle load
for the front and rear axles 86 and 87, respectively. In the same
manner as used in connection with the axle load determination for
an off-road truck, the moment arms about the front and rear axles
serve as the tools to determine the axle loads. Unlike the off-road
truck, the center of gravity for the load in the body 83 of the
scraper 81 cannot be as easily determined. In the off-road truck of
FIGS. 13a-b, the on-board weighing device combined with a pressure
sensor in the hoist cylinder system to find the center of gravity
for the load. In the scraper 81, the center of gravity for the load
of the scraper body 83 must be approximated. For illustration, the
scraper 81 in FIG. 14a is assumed to have a center of gravity at
the pivot point 88 of the pivot arm 89. With the location of the
center of gravity assumed, the total weight of the load can be
determined and, as a result, the forces on the axles can also be
determined.
To calculate the axle loads, the weight of the load must first be
determined. Converting the pressure in the hoist cylinder 82, while
the body 83 is in a raised position, to a force allows the moment
arm about the front axle to be solved for the weight of the body
83. Since the hoist cylinder 82 is at a slight angle .PHI. from
vertical, the force F.sub.2 must be multiplied by cos .PHI. to find
the vertical force for calculating the moment arm about the front
axle. The equation is as follows: ##EQU4## where F.sub.1 is the
weight of the body 83 and F.sub.2 is the force at the hoist
cylinder 82 lifting the body.
Once the weight of the load is determined, the axle loads are
easily calculated as follows: ##EQU5## where F.sub.4 is the weight
on the rear axle 87, and ##EQU6## where F.sub.3 is the weight on
the front axle 86. The foregoing calculation may be implemented by
the circuitry and flowcharts discussed in connection with FIGS. 16,
17 and 18a-r. Although the flowchart discloses steps for
calculating the axle loads for a dump body truck using data
gathered by the on-board weighing device and data from hoist
cyclinders, it will appreciated from the foregoing scraper
discussion that similar software steps may be used in connection
with the circuitry of FIGS. 16 and 17 to calculate scraper body
weight and axle loads.
As briefly mentioned earlier, the platform scale of FIGS. 15a-b may
be used to measure the tare weight for the front and rear axles of
the off-road truck of FIG. 13a-b or the scraper of FIG. 14a-d. The
tare weight is stored as a "hard number" in an electronic memory
and added to the calculated axle weights from the load in order to
arrive at the total axle loads. An exemplary platform scale may be
implemented by appropriate changes to the on-board weighing device.
Specifically, referring briefly to FIGS. 15a and 15b, an
inexpensive platform scale is illustrated using tubing, sensors and
support structure similar to that used for the on-board weighing
device. A plurality of tubing lengths 90 are positioned under a
surface plate 91. In order to hold the surface plate 91 in a stable
position to prevent sliding, two rows of pins 92 integral with the
plate are received in a corresponding two rows of sockets 93
integral with a bottom plate 94. Sensors (not shown) are attached
to one end of each tubing 90 or, if the tubing is crimped at its
center, the sensors may be attached to each end of the tubings.
A contact plate 95 interfaces the tubings 90 to the surface plate
91. The contact plate maintains a constant area of contact between
the surface plate 91 and the tubings 90. In order to prevent the
tubings from wandering on the bottom plate 94, each tubing 90 is
bordered along its length with projections 96 from the bottom plate
94. In operation, the platform scale is recessed into the ground in
order that the surface plate 91 is flush with the ground. In order
to weigh, for example, the front or rear axles of the truck in
FIGS. 13a and 13b, the truck operator merely drives the truck over
the platform such that all front or rear tires bear on the surface
plate. The pressure increases in the tubings 90 is sensed by the
pressure sensors and circuitry similar to that illustrated in FIG.
16 adds the individual pressure readings and converts the sum to a
weight measurement.
Referring now to FIG. 16, the electrical circuitry which completes
the weighing system by manipulating the pressure data received from
the on-board weighing device is provided by a sensor processing
unit 101 (previously referred to as the "processor means").
Preferably, the unit is microprocessor based. As will be apparent
to those skilled in the art, the sensor processing unit 101
includes a central processing unit 103 (hereinafter CPU 103), an
associated program memory in the form of a PROM 105 and read/write
memory RAM 107. A first memory portion of the RAM 107 functions as
a first storage array for pressure readings from the on-board
weighing device (hereinafter referred to as an ARRAY I). ARRAYS II
and III are for summaries and archives, respectively. The storage
arrays will be discussed in greater detail in connection with FIG.
16a. A particular example of a CPU suitable for the sensor
processing unit 101 is the Z80 microprocessor manufactured by Intel
Corporation of Santa Clara, Calif. Another possible microprocessor
is the 8085 from Intel.
In conventional fashion, emanating from the CPU 103 is a
microcomputer bus 109. The bus 109 is connected to the memories 105
and 107 as well as to input ports 113 and 115. The microcomputer
bus 109 communicates to a visual display unit 117 and a printer 119
by way of a display drive 120 and a printer drive 121,
respectively. In order to provide the sensor processing unit 101
with the operator and truck member, the microcomputer bus 109 is
connected to a keyboard 122 by way of an interface 124. The
keyboard 122 also provides the sensor processing unit 101 with a
conversion factor for converting the stored pressure readings to
weight values in tons, pounds or kilograms. Also, communicating to
the sensor processing unit 101 by way of the microcomputer bus 109
is a time clock 126. In order to provide a communications path
between the sensor processing unit 101 and the printer 119, the
visual display 117, the time clock 126 and the keyboard 122, the
microcomputer bus 109 includes data lines, memory lines and control
lines.
In order to measure the axle loads of the truck 11, an interrupt
instruction instructs to the sensor processing unit 101 to execute
the software routine for calculating the axle loads from pressure
readings of the on-board weighing device and the pressure sensor
139. As illustrated in FIG. 16, the interrupt signal is activated
by the truck operator by way of a push button 142. As mentioned in
connection with FIG. 13, the interrupt is activated only after the
operator has slightly raised the truck body 13 by extending the
hydraulic cylinders 19 and 21.
As previously mentioned, hauling parameters derived from the
on-board weighing device and processed by the sensor processing
unit 101 can be identified with particular I.D. numbers, thereby
providing an indication of truck and operator performance. It will
be appreciated by those skilled in the art that keyboard 122 can
also serve as an I.D. input for mechanics, oilers and other
maintenance personnel in order to record the maintenance work on
the truck (in a fifth array of RAM 107) and the identity of the
individual who performed the maintenance. In connection with
recording a user's identification number, the sensor processing
unit 101 controls an ignition lock-out device 127 which allows the
truck 11 to be started only if a correct I.D. number has been
received. In order for the sensor processing unit 101 to detect
changes in operator numbers when the truck is not running (for
instance, a change from a mechanic's I.D. to an oiler's I.D.),
power is continuously applied to the sensor processing unit. In a
well-known manner, the sensor processing unit 101 reverts to a
stand-by mode when the truck is turned off in order to reduce its
power consumption and thereby prevent a serious drain on battery
power. In the stand-by mode, the sensor processing unit
periodically powers up and looks to see if activity has occurred at
its sensor inputs. If, for example, a new I.D. number has been
entered into thekeypad 122, the unit stores the new number and
prints and/or displays a summary of data while the truck 11 was
under control of the previous number. (The foregoing display of
summary data will be explained in greater detail in connection with
FIG. 18i). As an alternative to entering the I.D. number by way of
the keyboard 122, an encoded card may be used by the operator in
connection with a card reader.
As will be explained in greater detail in connection with the
flowchart of FIGS. 18a-f, h-k, m, p and r, the sensor processing
unit 101 and its associated electronics are energized in response
to engine start-up. An engine start-up energizes the CPU 103 which
in turn initializes the program memory, thereby beginning the
program routine of the flowchart in FIGS. 18a-f, h-k, m, p and
r.
Each of the various alternative embodiments of the on-board
weighing device provide the circuitry of FIG. 16 with an analog
electrical signal which is linearly proportional to the pressure
exerted by the tubing fluid on the device's sensors 51a-d (tubing
in the preferred embodiment of the invention or load cells, strain
gauges or like pressure sensing transducers in alternative
embodiments of the invention). Since the pressure of the tubing
fluid is linearly proportional to the weight of the truck body 13
and since the sensors 51a-d reflect the tubing fluid pressure in a
linear fashion, the analog signals from the sensors are
proportional to the weight of the truck body.
Sensors 135, 137, 138 and 139 cooperate with the on-board weighing
device in order to provide information necessary for the sensor
processing unit 101 to provide output information to the truck
operator such as the loads on the front and rear axles as discussed
in connection with FIGS. 13a and 13b. The gear sensor 135 is used
in connection with a record keeping function performed by the
software of the sensor processing unit 101 such that, in response
to a gearshift by the truck operator, certain information stored in
RAM 107, and derived from the on-board weighing device, may be
manipulated (as explained more fully in connection with the
flowcharts of FIGS. 18a-f, h-k, m, p and r). In a similar manner,
the dump sensor 137 is utilized by the sensor processing unit 101
to manipulate stored data from the on-board weighing device when
the dump sensor 137 indicates that the truck body 13 has been
pivoted to its dump position. Preferably, the dump sensor is a
mercury switch mounted to the truck body 13 in order that it may
respond to the change in the body's position as a load is dumped.
Unlike mechanical switches, which are used in all prior apparatus,
to the best of applicant's knowledge, a mercury switch when
utilized as a dump switch offers the highly advantageous
characteristic of being isolated from the ambient conditions.
Therefore, the harsh conditions often encountered by off-road
vehicles will not cause a rapid deterioration of switch
performance.
The distance sensor 138 is used by the sensor processing unit 101
to provide the distance measurement in connection with the
calculation of tons-miles per hour units used to indicate the
degree of tire wear or use. Finally, the pressure sensor 139 is
located in the hydraulic line of the hydraulic cylinders 19 and 21
and provides a pressure measurement for use in connection with
calculating the axle distribution of the total load. The
interaction between the sensor processing unit 101, the on-board
weighing device and each of these sensors is discussed in greater
detail hereinafter in connection with the flowcharts of FIGS.
18a-f, h-k, m, p and r which disclose the program routine for the
sensor processing unit. All of the foregoing sensors are analog
devices which require analog-to-digital conversion as represented
by A/D block 130. As with A/D converter 129, the circuitry
comprising these converters is conventional and, therefore, will
not be discussed in detail.
In order to provide a visual indication of the unused weight
capacity of the truck body, the sensor processing unit 101 is
connected to a load indicator 140 by way of the microcomputer bus
109. The load indicator 140 includes a plurality of lights 140a-e
stacked one above the other. By activating a particular light on
the indicator 140, the sensor processing unit 101 is able to signal
the operator of the loader the proportion of a bucket load which
may safely be added to the truck without exceeding the weight
capacity of the truck. From a predetermined maximum weight capacity
for the truck stored in the sensor processing unit 101, the sensor
processing unit determines the remaining load capacity of the truck
body 13 from the current load as measured by the on-board weighing
device.
If the truck is loaded by a continuous flow of material, instead of
the incremental increase provided by the bucket of a front end
loader, the indicator 140 may provide a real time indication of the
percentage of remaining load capacity. For example, if a conveyor
belt or hopper (not shown) are used to load the truck 11, the
sensor processing unit can compare current load data with a maximum
load and activate an appropriate light 140a-e depending on the
fraction of remaining capacity. In this example, it is contemplated
the indicator light 140a corresponds to a remaining capacity of
20%, indicator light 140b corresponds to a remaining capacity of
15%, etc. The sequencing of the lights 140a-e as the truck
approaches full load will aid in the anticipation of when the
continuous flow should be cut off in order to avoid overflow, yet
assure a maximum load. The particular programming steps for
providing a real time indication of remaining capacity is not set
forth in the steps of the flowcharts in FIGS. 18a-f, h-k, m, p and
r, but the modifications required to the program for continuous
flow loading will be evident to a programmer from the flowchart
description of steps responsive to incremental loading.
In connection with the indication of the remaining weight capacity
of the truck, the sensor processing unit 101 determines the average
incremental increase in the weight of the truck body 13 with each
bucket from a loader, thereby indicating the average weight of a
bucket load used to load the truck body. If the average weight for
a bucket is less than the remaining weight capacity of the truck
body 13, then the green light 140a of the indicator 140 will be
activated by the sensor processing unit 101. If the average weight
of a bucket is greater than the remaining load capacity of the
truck body 13, the sensor processing unit 101 determines what
fraction of the average weight of a bucket the remaining weight
capacity most closely approximates.
Specifically, a three-quarter light 140b is activated if the
remaining weight capacity of the truck body 13 has a value between
three-quarters of an average weight for a bucket and the total
average weight for a bucket. In order to light the one-half light
140c, the remaining weight capacity of the truck body 13 must be
between one-half and three-quarters of the average weight of a
bucket. Similarly, in order to light the one-quarter light 140d the
remaining weight capacity must be between one-quarter and one-half
of the average weight of a bucket. Finally, for the red light 140e
to be activated and thereby indicate the truck body 13 is full, the
remaining weight capacity of the truck body 13 (as determined by
the pressure reading from the on-board weighing device) must be
less than one-quarter of the average weight of a bucket. The
manipulation of the indicator 140 by the sensor processing unit 101
in response to pressure readings from the on-board weighing device
will be explained in greater detail in connection with the program
routine of the sensor processing unit illustrated by the flowcharts
in FIGS. 18a-f, h-k, m, p and r.
A transceiver 150 is mounted to the truck 11 in an appropriate and
convenient location in order to enable the sensor processing unit
101 to communicate with a central computer. As will be explained in
greater detail hereinafter, the central computer serves as a
traffic cop to control the flow of trucks between load and dump
sites.
Turning now to the calibration and programmed operation of the
on-board weighing device and the sensor processing unit 101,
initialization of the system will be explained with reference to
the preferred embodiment of the invention. In connection with the
alternative embodiments of the on-board weighing device, the
modifications required to calibrate the sensor processing unit 101
and the modifications required to the program memory will be
obvious to those skilled in the art from the following detailed
description of the calibration of the on-board weighing device and
programmed operation of the sensor processing unit for the
preferred embodiment of the invention.
The calibration of the on-board weighing device may be illustrated
by considering the case of a truck body 13 having a ten-ton empty
weight and a 50-ton load capacity. In the preferred embodiment of
the on-board weighing device, if the tubings 47 have a total
combined effective surface area of 500 sq. in., the pressure
developed by the empty truck body 13 is 40 psi. A fully loaded
truck body 13 (i.e., 50 tons) develops a pressure of 240 psi. By
utilizing the pressure sensors 51a-d in connection with the tubings
47, an analog voltage output may be obtained which accurately
measures pressures between 0 and 300 psi. The analog voltage output
of the sensors 51a-d varies between two and six volts. For the
truck body 13 having an empty weight of ten tons and a full load
weight of 50 tons, the analog voltage from the sensors 51a-d is
2.53 volts for the weight of the empty truck body and 5.20 volts
for the full load weight. Therefore, the the voltage outputs of the
sensors have a voltage range of 2.67 from no load to full load
volts.
At the analog-to-digital converter 129 (hereinafter referred to as
an A/D converter) the output voltage from each of the pressure
sensors 51a-d is converted from an analog voltage to a digital
signal. The output from the A/D converter 129 is a binary-coded
decimal number which--since it is proportional to the analog
voltage from the pressure sensors 51a through 51d--is also
proportional to the pressure on the tubings 47. Since the voltage
output range of the pressure sensors 51a-d is between two and six
volts, the A/D converter 129 converts two volts to a binary-coded
decimal number close to zero (when the truck body is lifted off the
sensors thereby creating a zero load condition) and correspondingly
converts six volts to a binary-coded decimal number of
approximately 255.
For the exemplary truck 11 having a ten-ton empty weight for the
truck body 13, the foregoing calibration procedure provides, at the
binary-coded decimal output of the A/D converter 129, a decimal
number of 34 when the truck body is in its lowered position. In
comparison to the decimal number of 34 which represents an empty
load, for a full load of 50 tons the output of the A/D converter
129 is a binary-coded decimal number of 204. Therefore, a decimal
range of 170 represents all truck body loads from empty to full.
Therefore, with a pressure range of 200 psi (corresponding to a
weight range from no load to full load) a range of 170 in the
binary-coded decimal number from the A/D converter 129 gives a
resolution of approximately 1.18 psi per decimal number.
In order to calibrate the on-board weighing device for measurement
in an appropriate unit of weight (i.e., tons, pounds of kilograms),
a conversion factor, which corrects for the contact area between
the plate 60 (FIG. 6) and the desired units of weight, is manually
set into the keyboard 122 in FIG. 16 and converted to a
binary-coded decimal number by conventional circuitry associated
with the keyboard. This binary-coded decimal number is delivered to
the CPU 103 by way of the interface 124. At the CPU 103, the
conversion value is multiplied with a binary-coded decimal number
representing the previously calculated net pressure for the truck
body. The resulting binary-coded decimal product represents the
numerical value of the net weight of the truck body in tons, pounds
of kilograms, depending on the conversion factor chosen. For
example, the net pressure calculated from the pressure sensors
51a-d for a full load condition corresponds to a binary-coded
decimal number of 170. The CPU 103 multiplies the binary-coded
value of 170 by the binary-coded decimal number from the keyboard
122.
In order to obtain an accurate measurement of the pressure on the
four isolated lengths of the tubings 47, the sensor processing unit
101 reads the voltage 16 times in succession from each pressure
sensor 51a-d. In order to obtain one pressure value for each sensor
51a-d, the 16 readings are averaged. Each pressure sensor 51a-d is
read and averaged before the next sensor is read and averaged. When
all of the pressure sensors 51a-d have been read and their 16
separate readings averaged, the four average readings are
themselves averaged to obtain one pressure measurement for the
truck body 13. Since the net weight of the truck body 13 is the
weight of interest, the tare pressure (stored in memory as a
predetermined pressure) is subtracted from the average pressure
reading of the pressure sensors 51a-d to obtain a net pressure
reading. The net pressure reading corresponds to the weight of the
load carried by the truck 11 in its truck body 13. This reading is
stored in ARRAY I and is manipulated in accordance with the program
memory for the CPU 103 contained in the PROM 105.
In order to convert the foregoing pressure readings to a weight
reading, the effective area of contact between the tubing 47 and
the plate 60 (see FIG. 7) must be multiplied. The pressure data
from the sensors 51a-d represents weight per unit area. Multiplying
the effective contact area by the pressure data results in data
indicative of weight. Two methods may be used to find the
weight--(1) the average pressure may be multiplied by the total
effective area for all the plates 60 of the on-board weighing
device or (2) add the separate pressures from each of the sensors
51a-d and multiply the sum by the effective area of only one of the
plates 60. From empirical study, applicant has discovered that the
surface area of the plate 60 is not the precise area used to
multiply with the pressures. A slightly modified, enlarged surface
area is required in the calculation of weight. The degree of
enlargment is determined empirically. Of course, the pressure x
area product may also require conversion to provide the appropriate
weight units, e.g., pounds, kilograms, etc.
For the foregoing calculation of weight, the effective area of
contact between the tubing 47 and the plate 60 is considered to be
the same for each sensor 51a-d. If the specific system design
results in unequal areas, each pressure and area must be treated
separately. Therefore, if the four lengths of tubings 47 in FIGS.
1-4 include two short foreward sections and two long aft sections,
the two forward sections must be treated separately from the aft
sections in order to provide a meaningful single weight
calculation.
In order to record the relevant data provided by the on-board
weighing device and the electronic circuitry of FIG. 16, the RAM
107 is organized to not only include the miscellaneous temporary
storage (e.g., status flags) required for normal software
operation, but the RAM also includes arrays of data cells for
storing time and pressure data to provide a chronologicl record of
truck and operator performance and to provide a data base to
extract further data indicative of performance. Referring to FIG.
16a, the RAM 107 is schematically illustrated as including at least
a miscellaneous storage area and seven arrays.
ARRAY I provides storage locations for a plurality of consecutive
net pressure values calculated from the pressure sensors 51a-d of
the on-board weighing device. Also in RAM 107, storage locations
are provided for cataloging summaries of hauling parameters wherein
the summaries are indexed by operator number in order that the
performance of each operator of the truck 11 can be quantified. For
example, ARRAYS II and III are provided in RAM 107 wherein the
ARRAY II collects summaries of hauling parameters for a time
duration measured from the time a particular operator number is
entered into the system until the number is changed. Entry of a
particular operator number may identify a certain cell in the
second array for receiving summaries of hauling parameters, thereby
identifying the summaries with the operator. By providing a
non-volatile memory for the RAM 107, an ARRAY III serves as an
archive for the summaries in ARRAY II, thereby providing a record
of operator performance for a period of time including multiple
uses by the operator, e.g., a month, quarter or year.
A fourth array, ARRAY IV, provides a storage area for recording
maintenance work on the truck. Entry of a user I.D. number
indicative of maintenance personnel rather than drivers are stored
in ARRAY IV together with relevant data such as time under control
of the maintenance number. Two additional arrays, ARRAYs V and VI
store date useful in evaluating the performance of an off-road,
heavy duty truck and its loader. As will be discussed in greater
detail hereinafter, ARRAYs V and VI store data relating to the
weight of each bucket added by the loader and the real time of each
bucket addition. The purpose and manipulation of these stored
values in ARRAYs I-VI will be discussed in connection with the
flowchart of FIGS. 18a-f, h-k, m, p and r.
Finally, ARRAY VII is an area for storage data to be downloaded
from the on-board system to a remote central location for creating
a historical file. As will be apparent from the discussion in
connection with the flowcharts of FIGS. 18a-f, h-k, m, p and r and
20a-b, relevant data can be either or both displayed on-board and
downloaded to a central computer. If downloading is a selected
option, the data is temporarily stored in ARRAY VII for
transmission in response to receiving an appropriate control signal
from the central computer.
In a simpler, less costly device, the circuitry of FIG. 16 may be
replaced by a mechanical weight indicator 169 such as the one shown
in FIGS. 17a-c. The sensors 51a-d are removed from the tubings 47
and the oil is continuous from each of the tubings to one of the
piston chambers 170a-d. Within each chamber 170a-d is a piston
171a-d as exemplified by the piston in FIG. 17c, shown in
perspective. Each piston 171a-d is disk shaped and seals the
chambers 170a-d into top and bottom volumes with the aid of O-rings
172a-d.
Since the weight of the truck body 13 is proportional to the sum of
the pressures from the plurality of tubings 47 of the on-board
weighing device, the mechanical weight indicator 169 adds the
separate pressures and displays the total pressure by way of a
conventional pressure gauge 175. Once the system is calibrated, the
pressure gauge 175 may be supplemented with a weight scale such
that weight can be read directly from the gauge. It will be
appreciated from the following description that addition pistons
171 and piston chambers 170 may be easily added to the indicator
169 if more pressure inputs are required.
Referring to FIG. 17b, a plurality of pistion chambers 170a-d are
stacked one above the other and, they include pistons connected by
longitudinal shafts 176b-d as shown. Each of the shafts 176b-d
communicate the force from the piston below it to its piston.
Correspondingly, this latter piston adds the force on it from the
previous piston to the force from the oil pressure and passes the
sum to the next piston above it by way of its shaft 176, etc. The
last piston has the sum of all the forces from the pressures on the
other pistons below it. Since the lowermost piston 171a does not
have a piston below it, it does not require a shaft 176.
In order for the full force of one piston to be transferred to the
next piston, the top volume of each piston (except for the last or
uppermost piston) is vented to the atmosphere through vents 177a-c.
Of course, the oil intake ports 178a-d are located in the bottom
volume of each chamber 170a-d. In order to separate the bottom
oil-filled volume from an adjacent top, air-vented volume, chambers
170a-c include disk sections 179a-c, respectively. These sections
include central bores 180a-c, respectively, for receiving the
shafts 176b, c and d. Each central bore is sealed by a gasket. An
annular grove 181 in the ends of each of the chambers 170a-d
receives O-rings in order to provide a sealed indicator 169. Each
of the disk sections 179a-c include annular recesses on their top
and bottom surfaces for receiving the cylindrical chambers
170a-d.
In its assembled state, the mechanical weight indicator 169 is
capped by top and bottom plates 182 and 183, respectively. A
plurality of rods 184 in FIG. 17a extend the length of the
indicator 169 and join the top and bottom plates 182 and 183.
Threaded ends of the rods 184 receive nuts for securing the entire
assembly.
In order to equalize pressure between input lines during set up of
the indicator 169, valves 185a-c interconnect the input lines from
the on-board weighing device. During set-up, the valves 185a-c are
opened and the fluid pressure is allowed to equalize. The valves
185a-c are then turned off and, they remain off during normal
operation. In each of the lines from the tubings 47 is a flow
restrictor 186 for protecting against sudden changes in pressure
(i.e., spikes) from reaching the gauge 175. Also on each input line
is a air column 187 for protecting the on-board weighing device
from possibly drawing a vacuum in the event of a significantly
uneven distribution of weight. The top chamber 170d is filled with
fluid in both its top and bottom volumes in order that the added
pressure can be passed to the pressure gauge 175 by way of the top
volume and the output port 189.
In a simple system, the mechanical weight indicator may be located
off the truck and at a stationary site. For example, where the
loading equipment is stationary during loading, a coupling between
the on-board weighing device and the stationary mechanical weight
indicator may allow the operator of the loader to remotely monitor
the weight of the vehicle load without the need for relatively
expensive transceivers. Obviously, in such a system, the sensors
51a-d are absent and the coupling between the on-board weighing
device and the mechanical weight indicator is simply a conduit for
communicating the pressurized fluid from the truck to the statinary
location.
In order to allow the loaded vehicle to move away from the loading
site, the coupling between the on-board weighing device and the
mechanical weight indicator 169 includes a quick disconnect device
of conventional design. In operation, the vehicle is moved into
position for loading and the male and female members of the quick
disconnect device are joined so as to allow pressure from the
on-board weighing device to be directly transferred to the
stationary mechanical weight indicator 169. Since the loading
equipment is stationary, the indicator 169 is preferably mounted
directly to the loader so that the loader operator can monitor the
increasing weight of the load. When a full load is indicated, the
quick disconnect device decouples the mechanical weight indicator
169 and the on-board weighing device so that the truck may move
away from the loading site and allow a new truck to be positioned
for loading. The new truck is coupled to the mechanical weight
indicator 169 as before and the foregoing steps are repeated. An
obvious variation to the foregoing hydraulic system would be the
upgrading of the system to an electrical system wherein the sensor
51a-d are present on the on-board weighing device and a transmitter
porivides the means to communicate the pressure data to an
electronic weight indicator located at the loader. Of course, a
simplified version of the sensor processing unit 101 is necessary
in order to prepare the pressure data for transmission. The
stationary weight indicator may be merely a receiver of the data
which converts the transmitted pressure data to a weight display
for the operator of the loader.
Referring now to the flowchart of FIGS. 18a-18r, the main program
of the sensor processing unit 101 for executing all aspects of the
invention is illustrated by the flowchart in FIGS. 18a-18e. Various
subroutines are called from the main program for executing
particular aspects of the invention. These subroutines are
illustrated by the flowcharts in FIGS. 18f, h-k, m, p and r.
Although these flowcharts are intended to be complete for an
operating system, it will be understood that obvious modifications
may be made to the program if a user wishes to use less than all
aspects of the invention or, in the extreme, simply wishes to
transmit pressure data to a remote site as briefly discussed in
connection with FIGS. 17a-c.
For the purpose of reducing the complexity of the flowcharts, the
multiple steps required to calculate a single pressure value for
the pressure sensors 51a-d as described above are treated in the
steps of the flowchart as a single step. It will be understood,
therefore, that each step requiring the sensor processing unit 101
to read the pressure of the truck body requires the voltage signal
from each of the sensors 51a-d to be read in accordance with the
following protocol: (1) reading each sensor 16 times in succession,
(2) averaging the 16 readings, and (3) averaging the averaged
readings from all the sensors in order to obtain a single averaged
reading.
Upon starting the truck, the sensor processing unit 101 receives
power and starts the processing steps of the flowcharts. It begins
by initializing required values at step 210. From step 210, the
sensor processing unit 101 moves to step 230 where it reads the
time and date from the time clock 126 of the CPU. Next, as
indicated by step 240, the date, truck identification number, time
and operator identification number are printed by printer 119 or
transferred to ARRAY VII for later transmission via transceiver
150. (The truck I.D. number has been previously placed in permanent
memory.) As will become more apparent in connection with the
remaining explanation of the flowchart steps, virtually all data
identified for an output may be transferred to ARRAY VII in order
to download the data to a remote location. Radio link downloading
will be discussed in greater detail in connection with FIGS. 19a-c
and FIGS. 20a-b. The operator identification number is obtained
from the keyboard 122 as indicated by step 250. At step 260, a
count is preset to a maximum count in order to control later
sequencing of the software as explained more fully hereinafter.
After the truck has been turned on and the sensor processing unit
101 initialized in steps 210 through 260, the program moves to the
main program loop at step 269 where the distance recorded by the
distance sensor 138 is added to a previously calculated total
distance in order to update the total distance traveled by the
truck. From step 269, the program calls a Read Pressure Subroutine
(FIG. 18h) at step 270 wherein the unit reads the pressure from the
pressure sensors 51a-d and calculates an average pressure in the
manner previously described. In addition, the subroutine also
calculates a fore, aft and side-to-side pressure for use in
connection with other subroutines as explained hereinafter.
In step 275, the program compares the stored operator number with
the current operator number entered into the keyboard 122. If the
number is different, the new operator number is stored and the
program calls the Operator Summary Subroutine at step 277 for
analyzing hauling parameters measured during operation of the truck
11 while under the control of the previous operator. The Operator
Summary Subroutine is discussed in greater detail in connection
with FIG. 18i. After the Operator Summary Subroutine has been
executed or if a change in operator number did not occur in step
275, the program moves to step 280.
In step 280, the predetermined value for the tare pressure is
subtracted from the average pressure calculated in step 270 in
order to obtain a net pressure value. Since the tare pressure
represents the weight of the empty truck body, the net pressure
represents the weight of the load carried in the truck body 13.
From step 280, the sensor processing unit 101 moves to step 285
(FIG. 18b) where it is determined if the net pressure value is less
than zero. If the net pressure is found to be less than zero in
step 285, the program branches to step 286. In step 286, the
program zeros the net pressure and bucket pressure (bucket pressure
will be explained hereinafter in connection with the Load Analysis
Subroutine, FIG. 18k). At step 289, the net pressure is stored in
the first location of ARRAY I, i.e., ARRAY I(1). The most recent 16
net pressure values are stored in ARRAY I. These 16 values are
averaged in step 300 (FIG. 18b) in order to obtain a time averaged
net pressure.
In step 304, the program checks to determine if the operator has
activated the push button 142 (FIG. 16) to indicate that the axle
loads should be calculated. If the push button is pressed, the
program branches the main program and executes the Axle Load
Analysis Subroutine in step 305. As will be explained in greater
detail in connection with FIG. 18p, the Axle Load Analysis
Subroutine utilizes the net pressure reading for the truck body and
the net pressure from the pressure sensor 139 (FIG. 16) to
determine the loads on the front and rear axles.
Referring to FIG. 18c at step 380, the sensor processing unit 101
determines whether a gear shift has been sensed by the gear sensor
135. If it has, the program branches to step 390. In step 390, the
sensor processing unit 101 commands the printer 119 to print (or to
store in ARRAY VII) (1) the gear from which the truck has shifted,
(2) the most recently calculated average net weight, (3) the time
spent in the previous gear and (4) the distance traveled in the
previous gear (derived from the distance sensor 138 in FIG. 16).
Although not shown in FIG. 18c, a flag may be set in step 390
indicating a gear shift for use in connection with downloading data
to a central computer discussed in connection with FIGS. 19 and 20.
If the truck's gears have not been shifted in step 380 or after
completion of the printing function by the printer 119 in step 390,
the sensor processing unit 101 determines at step 395 whether the
time clock 126 is to be corrected (e.g., change to or from daylight
savings time).
If the time is to be corrected, the program branches to step 396
where the time correction is executed. From steps 395 or 396, the
program moves to step 400 and determines whether the dump sensor
137 has been activated. If the dump sensor has not been activated
at step 400, the program branches to step 405 to decide if 0.1
seconds have elapsed since leaving step 304 and entering step 405.
Since step 405 returns the program to step 380 if 0.1 seconds has
not elapsed, the delay gives the sensor processing unit 101 an
adequate time window for sensing the activation of the dump sensor
137 at step 400 before proceeding further in its program. If 0.1
seconds has elapsed in step 405, the program branches back to step
269 (FIG. 18a).
If the dump sensor 137 is determined to be activated in step 400,
the program moves to step 406 wherein a Dump Subroutine is called
which summarizes pertinent data of the haul cycle. In addition to
identifying, calculating and printing different parameters for a
single hauling cycle in the Dump Subroutine, it will be appreciated
that the data gathered by the sensor processing unit 101 from the
on-board weighing device and the associated sensors may be stored
in ARRAY II for a number of hauling cycles in order to provide
daily totals or averages of an operator such as, for example, the
total tonnage hauled per day, the number of loads hauled per day,
the average load hauled on a particular day and the average elapsed
time for a haul cycle. The Dump Subroutine is more fully explained
in connection with FIG. 18r. From step 406, the program calculates
the net pressure in step 410. As indicated in step 410, the
resulting single pressure value is stored in the RAM 107 at a
location designated for storage of a body-up pressure reading
(i.e., a pressure reading corresponding to the truck body raised
off the on-board weighing device).
In order to provide an indication for other parts of the program
that a dump has occurred, a dump flag is set in step 420. This
signal, with a gear change signal and a load signal (discussed in
connection with FIGS. 18k and m), provide sufficient information to
a central computer for it to control the distribution of trucks 11
to the loader 160 in a manner to minimize load cycle time. This
aspect of the invention will be discussed in greater detail in
connection with FIGS. 19a-b and FIGS. 20a-b.
In steps 430 and 435, a calculation is performed to update the
recorded amount of tire use. In step 430, the distance traveled
since the last calculation (the last calculation was taken when the
truck began loading as will be explained in connection with the
Load Analysis Subroutine of FIGS. 18k and m) is multiplied with the
total truck weight, i.e., the measured body weight plus the tare
weight of the truck. In step 435, the "ton.mile" data from step 430
is summed with prior "ton.mile" data. The total ton.mile data
provides an indication whether the tires of the truck 11 are
wearing in accordance with their ton.mile rating. This data can be
very important to a mine operator since reliable data regarding
tire wear is otherwise unavailable and since replacement of worn
tires is expensive. A calculation for ton.mile is executed by the
sensor processing unit every "segment" of a load cycle for which
there is a change in body weight; that is, at the end of a haul
after the truck has traveled from loader to dump site and at the
beginning of a haul after the truck has traveled from the dump site
to a loader. The time for the current segment of the load cycle is
stored in step 440. The elapsed time indicates how long it took for
this load to be delivered to its destination, i.e., from last dump
to present dump.
By printing in step 450 (or storing in ARRAY VII for later
transmission) the current average net weight (calculated in the
subroutine of FIG. 18f) in response to activation of the dump
sensor 137, the sensor processing unit 101 provides a hard copy of
the truck's load immediately before the load is dumped by the
pivoting of the body about hinge assemblies 17. The elapsed time
for this load cycle is also printed. The current time is read in
step 455. Finally, if it is determined at step 460 that the current
time is greater than the last full hour of the time last read in
step 460 plus one, the CPU 103 commands the printer 119 to record
the time of the dump in step 470. In order to initialize step 460
for its next execution, step 475 sets the present whole hour equal
to the previous hour.
Referring to FIG. 18d, in order to re-initialize the sensor
processing unit 101 after a load has been dumped, the net pressure
array, i.e., ARRAY I, is filled at all of its 16 locations with the
body-up pressure calculated during step 410. After this "packing"
of ARRAY I in step 480, the sensor processing unit 101 reads the
pressure at the pressure sensors 51a-d in step 490 in accordance
with the same procedure as previously described. At step 500, that
pressure value is stored in one of the storage cells in ARRAY I,
thereby replacing one of the body-up pressures "packed" into the
array. From the 16 values in ARRAY I, an average pressure is
calculated at step 510.
At step 520, the sensor processing unit 101 determines if the
average pressure calculated in step 510 is greater than the body-up
pressure plus a constant. The constant is added as a buffer in
order to ensure the truck body 13 is lowered onto the tubings 47
before the program progresses to the next step. Since initially at
step 520 the ARRAY I is packed with the body-up pressure (except
for the one reading obtained and stored during steps 490 and 500,
respectively), the average pressure calculated from ARRAY I is
approximately equal to the body-up pressure. Therefore, if the
average pressure is less than the body-up pressure plus a constant
in step 520, the sensor processing unit 101 returns to step 490 via
step 521 where another pressure reading is made and the resulting
pressure is stored into ARRAY I at step 500. With each storage of a
new value in ARRAY I, the oldest value is dropped. The average
pressure is again calculated at step 510 from the values in ARRAY I
and the resulting value is compared to the body-up pressure plus a
constant to determine if the truck body has been lowered onto the
tubings 47. Steps 490-520 are repeated until the average pressure
calculated from ARRAY I reaches a value (because of the lowering of
the truck body 13) that is greater than the body-up pressure plus a
constant. When this occurs the sensor processing unit 101 will
branch from step 520 to step 524 in the flowchart.
Since a negative decision in step 520 indicates the truck body is
not fully resting on the on-board weighing device, step 521 checks
to determine if the truck is moving before returning the program to
step 490. Moving the truck with the body raised may cause serious
damage to the hinge assemblies 17 and/or the hydraulic cylinders 19
and 21. If it is determined in step 521 from the distance sensor
138 that the truck is moving, the flowchart branches to steps 522
and 523 wherein the distance traveled is recorded and updated and
where a status flag is set for use in connection with step 524.
If the test in step 520 indicates the truck body is completely
lowered, the program leaves the loop of steps 490-523 and branches
to a test in step 524 in which the status flag of step 523 in
investigated. If it has been set, the truck has been moved before
the body was fully lowered. Therefore, step 524 branches to step
525 and 526 in response to a set condition of the status flag. In
step 525, a running total is kept of the number of dumps for which
the truck was moved before the body was fully lowered. Step 526
resets the status flag.
In order to check for a haul-back condition--i.e., not all of the
load was dumped--step 527 investigates the pressure from the
on-board weighing device to determine if the pressure is greater
than tare pressure plus a predetermined margin. In the exemplary
embodiment, the margin is seven percent of the optimum load. A
determination in step 527 that the average pressure is too great
and a haul back condition exists will result in the printing of the
operator's number by the printer 119 in step 528 and/or a flashing
of the operator's number on display 117 (or storing this data in
ARRAY VII for downloading). From steps 527 or 528, the program
moves to step 530 in FIG. 18e where the CPU 103 reads the current
time for use in connection with a later step.
Referring now to FIG. 18e, at step 540, the gear sensor 135 is
again checked to see if a gear shift has occurred. If it has, the
program branches to step 550 where the following information is
printed by the printer 119 (or transferred to ARRAY VII)--gear
shifted from, most recently calculated average net weight, elapsed
time in the previous gear and distance traveled in previous gear.
As with step 390 in FIG. 18c, the gear change in step 540 may be
stored as a status flag in order for it to be included with the
downloading of data to a central computer as discussed hereinafter.
At step 560 the sensor processing unit 101 determines if 25 seconds
have elapsed since the time read in step 530. If it has not, the
program returns to step 540 and the unit 101 again checks to see if
there has been a shifting of gears. The delay of 25 seconds
implemented at step 560 insures that the truck body 13 has
sufficient time to fully settle on the truck frame 15 before the
sensor processing unit 101 continues through its calculations.
After 25 seconds have elapsed, the sensor processing unit 101 moves
forward to step 570 where a new net pressure reading is calculated
and loaded into each of the 16 locations of ARRAY I. From the 16
net pressure readings in ARRAY I, a single average net pressure
reading is calculated at step 580. From step 580, the sensor
processing unit 101 branches back to the beginning of the main loop
of the program at step 269, flagged as "A" in the flowchart.
A periodically generated (for example, two seconds) timer interrupt
causes the sensor processing unit 101 to execute the steps of the
subroutine in FIG. 18f. This subroutine determines whether an
increase in current pressure is attributable to a spike (from rough
road conditions) or the addition of a bucket. If it is determined
the former is the cause of the pressure increase, the subroutine
records the increase as a spike in order to monitor road condition;
alternatively, if it is determined a bucket has been added, a
series of steps are executed to update the load status of the
sensor processing unit 101.
Referring to the particular steps in FIG. 18f, an internal counter
of CPU 103 is checked in step 582 to determine if the predetermined
maximum count set in step 260 of FIG. 18a has been reached. The
predetermined maximum count equals the number of cells in ARRAY I
in order that successive average pressure values calculated in the
subroutine represent completely different sets of pressure data. If
the value of the counter exceeds the number of cells in ARRAY I,
the program branches from step 582 to step 584 wherein the current
net pressure is examined to determine if it is greater than the old
net pressure reading plus a constant. The constant is a number
which is intended to identify pressure increases from the last
average which are great enough to be identified if they later prove
to be pressure spikes resulting from rough road conditions. If the
current net pressure is greater than the old net pressure plus a
constant, the program resets the counter at step 586. Otherwise,
the program branches to step 616 whose function will be discussed
later. By setting the counter to zero, the next interrupt will
result in step 582 branching to 588, instead of step 584 as
before.
In step 588, the counter is increment and then examined, in step
590, to determine if the counter has reached the maximum count
(equal to the number of array cells in ARRAY I). If the count is
less than the maximum count, the readings in ARRAY I are not
necessarily all new redings with respect to the last average
reading. Therefore, the program bypasses the calculation of a new
average net pressure and associated program steps by branching to
step 616.
If the current count equals the maximum count, then the program
moves to step 592 wherein the current average net pressure from
ARRAY I is compared to the old average net pressure plus a constant
to account for hardware error from devices such as A/D converter
129 (the old average net pressure is the average net pressure which
served as the current net average pressure the last time step 592
was answered yes). If the current net average does not exceed the
old net average, then the increase in pressure which caused the
counter to reset in steps 584 and 586 must have been a spike and
not a sustained increase in weight indicative of an added bucket.
Therefore, the program branches to step 594 wherein the size of
ARRAY I is increased to 24 and the corresponding maximum count is
increased to 24. By increasing the size of ARRAY I, more readings
will comprise each average thereby mitigating the effect of
pressure spikes. In order to monitor the roughness of the road, the
pressure spikes are recorded in step 596. From step 596, the
program branches to step 616. In step 616, the weight displayed by
the LED display 117 (FIGS. 2b and 16) is refreshed. Alternatively,
or in addition to this, new weight data can be transferred to ARRAY
VII for downloading to a remote site via a radio link.
If the current average net pressure is greater than the old average
net pressure plus an error factor, than a sustained increase in the
load is indicated, i.e., a bucket has been added. Therefore, the
load is updated in steps 598-608. In step 598, the current average
net pressure is converted to weight in preparation for display.
Because the truck is being loaded (as indicated by an added
bucket), the truck can be assumed not to be moving; therefore,
spikes are unlikely to occur. Based on the foregoing assumption the
size of ARRAY I is reduced to 16 in step 600 in order to provide
more frequent averages (the maximum count is also set at 16). In
order to provide an old net average pressure and an old net
pressure for the next interrupt in which the count equals the
maximum count, the present average net pressure and present
instantaneous net pressure are designated old pressures in steps
602 and 604.
Since the truck 11 is in the process of loading, a Load Imbalance
Subroutine is called in step 606 and a Load Analysis Subroutine is
called in step 608. These subroutines will be discussed in detail
in connection with FIG. 18j and FIGS. 18k and m, respectively. From
steps 590, 608, 584, 586 or 596, the program updates the average
weight shown on the display 117. Of course, if steps 598-608 have
been bypassed, the updated average weight is the same as the old
average weight. After the routine of FIG. 18f has executed its
steps, the sensor processing unit 101 returns to the main program
of FIGS. 18a-18e.
Turning to the subroutines illustrated by the flowcharts in FIGS.
18h-k, m, p and r, each subroutine is called from the main program
represented by the flowchart in FIGS. 18a-f. For the Read Pressure
Subroutine of FIG. 18h, the subroutine is called from step 270 in
the main program. In the first step of the subroutine, a single
average pressure reading is obtained in step 620 for the on-board
weighing device in the manner previously described. From step 620,
the subroutine calculates fore and aft pressures in steps 630 and
640, respectively. In order to calculate the aft pressure, the
average pressure readings from the rearwardly positioned sensors
51b and 51d are averaged. Correspondingly, in order to provide a
forward pressure, the pressure values from the forwardly positioned
sensors 51a and 51c are averaged. These fore and aft pressure
readings are used in connection with the Imbalance Subroutine
called in step 606 and set out in FIG. 18j.
In steps 650 and 660 of the Read Pressure Subroutine, the
side-to-side pressure of the truck body on the on-board weighing
device is determined. Specifically, in step 650, the averaged
pressure readings from sensors 51a and 51b on a first side of the
truck 11 are averaged in order to provide a pressure for the first
side. Correspondingly, for the opposite side, the averaged pressure
readings from sensors 51c and 51d are averaged. As with the fore
and aft pressure readings, the side-to-side pressure readings are
used in connection with the Imbalance Subroutine of FIG. 18j. After
the pressure sensors 51a-d have been read and the appropriate
pressure measurements calculated, the subroutine returns to the
main program at step 275.
Referring to the Operator Summary Subroutine in FIG. 18i, data
indicative of operator performance may be gathered and stored
during truck operation under the control of a particular operator
number and thereafter summarized and displayed or printed when the
operator number is changed. Although the steps of FIG. 18i are
described in connection with organizing data in connection with an
operator number, it will be appreciated that the number, input via
keypad 122, need not only be indicative of an operator change, but
it may also be indicative of changes in truck status occurring
while under the control of a single operator, e.g., hauling, break
time and other identifiable time segments in a daily routine. For
example, summaries in accordance with FIG. 18i may be kept for the
duration of the control by an operator, but entry of an additional
number via keypad 122 may be recognized by the sensor processing
unit 101 as identifying a loader for which summaries are also to be
kept. When the truck is directed to a different loader, the
operator merely enters the new loader number into the sensor
processing unit 101 via the keypad 122 and, in response to the
number change, the unit outputs the performance summaries while the
truck was loading from the previous loader. From the foregoing,
other natural extensions of this concept exemplified in FIG. 18i
will be obvious to those familiar with mining management.
The flowchart for the Operator Summary Subroutine sets forth
exemplary types of data that can be stored and summarized by the
on-board weighing device during its normal operation. For example,
since the on-board weighing device calculates the total load for
each hauling cycle, the load may be stored and accumulated for all
the hauling cycles for a particular truck operator number. By
accumulating pressure readings from the on-board weighing device
which reflect the total tonnage hauled by the operator, useful
information indicative of operator performance can be obtained.
In order to mark the end of the time interval for which the truck
was under the control of the previous operator number, the present
time is read in step 669. In step 670, the current time or real
time in step 669 is designated as the "new operator time". To find
the elapsed time of control under the previous operator, the old
operator time is subtracted from the new operator time in step 671.
In order to prepare for the next operator change, step 672 sets the
new operator time identified in step 670 equal to the old operator
time. In step 673, the total tonnage hauled is divided by the total
number of buckets (which is also counted and accummulated) in order
to give an indication as to the average weight for each bucket. The
weight of the average load is found in step 674 by dividing the
total tonnage hauled by the total number of loads. In addition, in
step 675, the total number of spikes recorded during the hauling
cycles is divided by the total number of loads to provide an
average number of spikes for the loads which is indicative of the
degree of road roughness. To provide an indication of wire tear,
the subroutine calculates a value for tons-miles per hour in step
676 by dividing the total "ton.mile" from step 435 by the total
time under operator control. In order to display the average time
for a haul cycle, step 677 divides the total time under operator
control by the total number of loads by the operator. To find the
average distance traveled per load cycle with the body of the truck
raised, step 678 divides the total body-up distance (from step 522)
by the number of body-up loads (step 525). The foregoing data is
stored in ARRAY III of RAM 107.
In step 680, the average number of buckets per load is calculated
from information accumulated during the hauling cycle i.e., the
total number of buckets from step 790 and the total number of loads
hauled by the operator. In step 690, the average time between
buckets is calculated. Since the addition of each bucket is sensed
by the routine of FIG. 18f, the time between successive buckets is
easily determined (in step 850). By summing the times and storing
the sum in ARRAY II, the average time between buckets for an
operator can be calculated and printed. This average will give an
indication of possible problems during the loading cycle. In step
700, the longest time interval between buckets for each hauling
cycle (from step 1020) is summed and divided by the total number of
hauling cycles to give a value indicative of the averge maximum
interval between buckets for the operator. Finally, in step 710 the
average values calculated in steps 670-700 are printed by printer
119 in order to give the operator and his employer a hard copy of
the foregoing hauling parameters. Of course, as with the previous
data outputs, this data may be transferred to ARRAY VII to await
downloading to a central computer via a radio link established by
the on-board transceiver 150. From step 710, the subroutine returns
to the main program at step 280.
Referring now to FIG. 18j, the Imbalance Subroutine called from
step 606 in the routine of FIG. 18f tests to determine if the
weight distribution of the load carried by the truck body 13 is
significantly imbalanced. In step 720, the Imbalance Subroutine
checks to determine if the most recent net pressure reading is
greater than 65 percent of a predetermined maximum load pressure.
If the truck body 13 has not yet been loaded to this percentage of
its capacity, then the program will exit the subroutine and return
to the main program at step 608 in FIG. 18c. When the truck body
has been loaded to a weight which is greater than 65 percent of the
maximum load the Imbalance Subroutine will test for side-to-side
imbalance and fore-and-aft imbalance in steps 730 and 740,
respectively.
In step 730, the side-to-side balance is tested by determining if
the optimum balance ratio (i.e., 1.0) multiplied by the pressure of
the second side and subtracted from the pressure of the first side
has an absolute value greater than, for example, ten percent of the
truck's load capacity. If the test in step 730 indicates an
imbalance of the load, the subroutine activates the display 117,
audio output 196 (FIG. 2b) and/or printer 119 (FIG. 16) at step 750
in order to warn the operator of the truck. This data may also be
downloaded via ARRAY VII. From step 750, the program checks for
fore-and-aft imbalance at step 740. Alternatively, if a
side-to-side imbalance is not indicated by the test in step 730,
the subroutine branches directly to step 740 where a algorithm
similar to the algorithm in step 730 is utilized to test for a
fore-and-aft imbalance. (The optimum ratio for fore-to-aft balance
may be, for example, -3 to +3.) If a fore-and-aft imbalance is
indicated in step 740 the program moves to step 760 wherein the
display 117 inbalance signal 197 (FIG. 2b) and/or printer 119 (or
other indication such as truck mounted light 197 to alert loader
operator) is activated to alert the truck operator that the truck
body is loaded in an imbalanced condition which may cause damage to
the truck (this data may also be downloaded via ARRAY VII). From
the Imbalance Subroutine, the program moves to the Load Analysis
Subroutine.
Referring now to FIG. 18k, the Load Analysis Subroutine provides
data related to the loading of the truck body by a loader using a
bucket to load the body. By analyzing and summarizing data related
to the buckets which incrementally load the truck body, useful
information regarding the efficiency of the hauling cycle can be
obtained. The Load Analysis Subroutine is called from the routine
of FIG. 18f if it is determined at step 592 that the current
average of the net pressure readings in ARRAY I is greater than the
old average net pressure plus a predetermined constant. As
explained in connection with FIG. 18f, when the current average of
the net pressure readings in ARRAY I is greater than the old
average of the net pressure plus a constant, it can safely be
assumed a bucket has been added to the body of the truck;
therefore, the Load Analysis Subroutine will be executed starting
at step 770 wherein a new bucket pressure is calculated by
subtracting the old average net pressure from the current average
net pressure.
In step 780, an average value for the bucket pressure for this load
is calculated by multiplying the previous average bucket pressure
per load by the number of previous buckets per load and adding the
product to the new bucket pressure calculated in step 770. The
foregoing sum is then divided by the number of buckets per load
which is the number of previous load buckets plus one. In steps 790
and 800, the subroutine updates the number of total buckets and the
number of buckets for the current hauling cycle, respectively. In
steps 810-815, the time of the bucket is recorded for use in
connection with steps in the Load Analysis Subroutine to be
discussed hereinafter.
In step 820 of the Load Analysis Subroutine, a test is conducted to
determine if the current bucket is the first bucket of a hauling
cycle. If the current bucket is the first bucket of a hauling
cycle, the program branches to steps 825-829 before returning to
the main program loop at step 616 in FIG. 18c. For use in
connection with later calculations related to bucket loading time
and total buckets, step 825 renames the "new bucket time" as the
"old bucket time" and initializes ARRAYS V and VI of RAM 107. For
use in connection with communicating with a central computer for
controlling the flow of the truck fleet, a load flag is set in step
827. This flag is used in connection with transmitting data from
the on-board weighing device to a central computer as will be
explained in greater detail in connection with FIGS. 19-20.
Finally, in steps 828 and 829, a fresh ton.mile rating is taken
which corresponds to the ton.mile rating for the haul segment from
the dump site to the load site.
If the current bucket is not the first bucket of a hauling cycle,
the program branches from step 820 to steps 830-860. In step 830, a
calculation is made of the elapsed time between the addition of the
current bucket and the time at which the previous bucket was added
at step 830. In step 840, the bucket times are updated in order to
prepare the data for the next bucket. In step 850, the elapsed time
between the current bucket and the previous bucket is added to a
running total of time intervals between buckets to provide a total
elapsed loading time. This total elapsed loading time is used in
connection with step 690 of the Operator Summary Subroutine in
order to provide data indicative of truck and operator
performance.
In order to store the net pressure of each bucket, step 852 loads
ARRAY V with the pressures for all the buckets of a current load
cycle. The last cell, N, in ARRAY V is used as a storage location
for the value of the average bucket weight for a load. In
connection with the storage of these pressures, step 855 stores the
elapsed time between the addition of buckets in a load cycle in
ARRAY VI. The data in ARRAYs V and VI may be used in connection
with providing a detailed performance report of each load
cycle.
In step 860-885, the longest elapsed time between buckets is found.
In step 860, the program tests to determine if the current bucket
is the second bucket. If the current bucket is the second bucket,
then the program automatically designates the current elapsed time
between buckets as the maximum elapsed time between the buckets in
step 870. Alternatively, if the current bucket is not the first or
second bucket as determined in steps 820 and 860, the program will
branch to step 880 wherein the current elapsed time between buckets
is tested to determine if it is greater than the maximum elapsed
time between buckets previously recorded. If the current elapsed
time between buckets is not greater than the previously recorded
maximum elapsed time between buckets, the program branches to step
890 (FIG. 18m); otherwise, the program designates the elapsed time
between buckets as the new maximum elapsed time between buckets at
step 885. The maximum elapsed time is used in connection with step
700 of the Operator Summary Subroutine.
Referring now to FIG. 18m, the current average net pressure is
tested to indicate whether the load of the truck body is
sufficiently close to the maximum load capacity of the truck such
that further addition of material by a full bucket would overload
the truck body. In order to prevent the truck from being
overloaded, steps 890-920 test to determine if the remaining
capacity of the truck body 13 is less than the weight of an average
bucket for this load as calculated in step 780 of the
subroutine.
Specifically, in step 890 the average net pressure is compared with
the predetermined maximum of the truck body minus one-quarter of
the average bucket. If the average net pressure is greater than the
maximum load minus one-quarter of the average bucket, the truck
body will be overloaded by the addition of as little material as
fills one-quarter of the bucket. Therefore, the subroutine branches
to step 895 wherein the red light 140e of the load indicator panel
is activated. The red light 140e serves to warn the loader operator
that the truck body 13 is loaded to a capacity which any further
loading would overload the truck body.
If the average net pressure is not greater than the maximum load
minus one-quarter of the value of an average bucket the subroutine
moves to step 900 wherein the current average net pressure is
compared with the predetermined maximum load minus one-half the
value of an average bucket. If it is determined that the current
average net pressure is greater than the maximum load minus
one-half the average bucket, the subroutine branches to step 905
wherein the one-quarter yellow light 140d of the load indicator 140
in FIG. 16 is activated. For the loader operator, the one-quarter
yellow light 140d indicates that the loader may add further
material to the truck body 13 but only an amount less than
one-quarter of the volumetric capacity of the bucket of the
loader.
If the test in 900 determines that the average net pressure is not
greater than the maximum load minus one-half the average bucket,
then the subroutine tests at step 910 to determine whether the
current average net pressure is greater than the maximum load minus
three-quarters the value of the average bucket. If a positive
determination is made in step 910, the subroutine branches to step
915 wherein the one-half yellow light 140c is activated on the load
indicator 140. In a similar manner as the one-quarter yellow light
140d, the one-half yellow light 140c indicates to the operator of
the loader that the next bucket of material must fill the bucket no
greater than one-half the volume of the bucket in order to avoid
overloading the truck 13.
If the test in step 910 is negative, the subroutine tests to
determine if the current average net pressure is greater than the
predetermined maximum load minus a full average bucket. If the test
in step 920 is positive, the subroutine activates the three-quarter
yellow light 140b of the load indicator 40 in step 925. If the test
step 920 is negative, the green light 140a of the load indicator
140 is activated in order to indicate to the operator of the loader
that a full bucket load of material may be added to the truck body
13 without overloading the body. From steps 890-926, one of the
lights 140a-e on the load indicator 140 will always be activated
during the loading of the truck body 13.
Digressing briefly to FIG. 16, the lights 140a-e of the load
indicator 140 are positioned in a stacked arrangement such that
there relative positions give an indication of the degree of
remaining truck capacity. Specifically, the green light 140a
occupies the lowermost position in the stack of lights 140a-e,
thereby indicating that the truck body has capacity for a full
bucket load. The red light 140e at the top of the stack, indicates
the truck body is full and no further bucket loads can safely be
added. The three lights 140b-d are positioned intermediate the
green and red lights in order to indicate weight capacities
intermediate the full bucket capacity symbolized by the green light
140a and no remaining capacity symbolized by the red light
140e.
Referring now to FIG. 18p, the Axle Load Analysis Subroutine is
called from the main program at step 305 when a determination is
made in step 304 that the operator has called for an analysis of
the axle load. As explained in connection with the illustration of
FIGS. 13a and 13b, the pressure in the hoist cylinders 19 and 21 is
required to calculate the distribution of the load between front
and rear axles. Accordingly, in step 928 the pressure from sensor
139 (FIG. 16) is read by the CPU 103 and converted to a weight
measurement. In order to get a total body weight, the weight of the
load derived from the current average pressure is added to the tare
weight of the truck body in step 929. In step 930 the center of
gravity for the load is calculated from the total weight and the
weight measurement from the sensor 139 in the hoist cylinder
system. The particular algorithm used in step 930 in order to
calculate the location of the center of gravity for the load is set
forth as equation 2 in connection with FIGS. 13 a and 13b. With the
center of gravity for the load known, the distribution of the load
over the front and rear axles is determined in steps 940 and 950,
respectively, using equations 4 and 6.
In step 960 the tare weights for the front and rear axle are added
to the axle loads for the front and rear axles calculated in steps
940 and 950. Therefore, the adjusted pressure readings for the
front and rear axles obtained from step 960 reflect a total weight
over the front and rear axles. Finally, in step 980, the subroutine
commands the printer 119 to print the weights bearing on the front
and rear axles (or store in ARRAY VII).
Turning now to FIG. 18r, the Dump Subroutine is called by step 406
of the main program after the dump sensor has been activated as
detected in step 400. The Dump Subroutine summarizes selected
parameters at the end of a hauling cycle which is indicated by the
activation of the dump sensor 137. In step 1000, the current
average net weight is added to the total of previous weights hauled
in order to provide the total tonnage hauled by the truck while
under control of the operator. The total tonnage hauled is used in
connection with the Operator Summary Subroutine. Because the
activation of the dump sensor 137 indicates an end to a hauling
cycle, the number of buckets per load and the average bucket
pressure per load are set equal to zero in step 1010 in order to
initialize these values for the next hauling cycle. In step 1020, a
total maximum elapse time between buckets is updated by adding the
maximum elapsed time between buckets for the last load cycle.
In order to record the number of hauling cycles, step 1030
increments a stored number identified as "total number of loads"
which is used in connection with the Operator Summary Subroutine to
provide averaged data indicative of operator performance. In order
to keep track of road roughness, the total number of spikes
recorded during a hauling cycle is accumulated in step 1040 with
the number of spikes during previous hauling cycles. The total
number of spikes is used in connection with the Operator Summary
Subroutine in order to provide an indication of road quality.
Following step 1040, spikes are set equal to zero in order to
provide a frsh basis for accumulating spikes in the next load
cycle.
In step 1050, a test is conducted to determined whether the current
average net pressure is greater than a predetermined maximum
pressure which corresponds to the maximum weight capacity of the
truck. If the test in 1050 is positive, the overloading of the
truck is recorded in steps 1060-1080. In step 1060, an overload
counter is incremented to indicate that the present hauling cycle
was an overload cycle. In step 1070, the amount of overloading or
"overage pressure" is calculated by subtracting the average net
pressure from the maximum allowable pressure. The average pressure
for the present hauling cycle is added to a total overage pressure
for all hauling cycles in order to provide a pressure value
indicative of the total weight by which the truck has been
overloaded. From either step 1080 or from a negative indication in
step 1050 the Dump Subroutine moves to step 1090 wherein the
printer 119 (FIG. 16) is activated to print the weight of each
bucket for the just completed haul cycle (stored in ARRAY V) and
the elapsed time between each bucket (stored in ARRAY VI). This
data may also be transferred to ARRAY VII for downloading.
As is apparent from the foregoing description, large amounts of
data are gathered from the on-board weighing device and related
on-board sensors. When a plurality of trucks in a fleet are
equipped to collect such data, in order for this data to be of the
most benefit to fleet operators, this data needs to be downloaded
for long term storage and analyzation in order to create and
maintain a historical file of truck fleet activity and performance.
Obviously, the printer 119 provides a permanent record. However,
for large fleets it is cumbersome, at best, to store this data in
this form with an intent of later analyzation and reference.
Therefore, to allow the data generated to be more easily
manipulated and analyzed, the sensor processing unit 101 may be
coupled to a storage memory such as a cassette tape or non-volatile
memory pack in order to download the ARRAYS when they reach their
capacity. However, downloading in this manner is not on a real time
basis and it requires operator or management intervention in order
to assure the downloaded data is collected in a timely manner i.e.,
collection of paper tape.
For the data generated by the sensor processing unit 101 to be of
the greatest benefit and value it needs to be gathered and analyzed
on a real time basis (as opposed to gathering paper tapes at the
end of a work cycle) so that as data is generated by a fleet of
trucks it can be immediately gathered to provide a real time
analysis of fleet operations. Therefore, preferably, and in
accordance with the invention, the accumulating real-time data can
be of the most value if it is downloaded by a radio link from the
on-board device to a remote fixed location where a historical
real-time file can be created and analyzed in order to give
management personnel at a remote site a current indication of truck
fleet performance. By analyzing the downloaded real-time data on a
historical real-time basis, the loaders of the trucks may also be
evaluated. As a feature of the real-time data gathering by radio
link data downloading, each truck in a fleet is able to communicate
with a central computer via radio links with one or more repeater
points. As this occurs, these repeater points can in turn
communicate back data from the central computer to the individual
trucks; Therefore, instructions/directions can be sent selectively
to trucks.
Referring to FIG. 19a, in mining operations or similar type
hauling, it is not unusual for there to be simultaneously hauling
of overburden, coal or the like. Also, in large operations, more
than one loader 160 services the truck fleet and there may be more
than one dump site. Gathering data generated by the sensor
processing unit 101 and controlling traffic flow from the dump
sites to the loaders 160 or vis-versa becomes unwielding, and
therefore inefficient, when the mining operation is large and many
trucks and loads are involved. As a function of its data gathering
capabilities, the on-board weighing system described herein allows
the electronic system of FIG. 16 to accurately record the elapsed
time of a hauling cycle or segments thereof and, since the on-board
weighing system provides an indication to the electronic system
when a load cycle begins and ends, as a transceiver 150 is mounted
to each truck 11 (illustrated in FIG. 19a) for data downloading
with a central computer 155. This data when gathered by the central
computer 155 and analyzed can be utilized by the central computer
to provide instructions and directions for efficient traffic
control and remote monitoring of truck performance. Other data, in
addition to the above, as outlined in the flowcharts of FIGS. 18a-r
is also downloaded to the central computer 155 for storage and
analysis from the on-board weighing device. As will be explained in
greater detail hereinafter, data downloading communication between
the trucks 11 and the central computer 155 is handled by
strategically located repeaters 160a and 161 in FIG. 19a.
The central computer 155 receives data from the electronic
circuitry on the truck 11 by way of the radio (or hard wire) links
157 (or hard wire links from stationary pick up points such as dump
sites). In order to provide a two-way link, the central computer
155 includes a transceiver 155a. Data received from the trucks 11
is processed by the CPU 155b with the aid of PROM 155c and RAM
155d. The CPU 155b communicates to the PROM 155c and RAM 155d along
a bus 155e in conventional fashion.
Because the on-board weighing device and its associated circuitry
determines when a load cycle starts (the first bucket is sensed)
and ends (first gear shift after first bucket) and when a dump
begins (as well as other operating data), the central computer 155
is able to use this data to provide efficient instructions and
directions for controlling movement of the trucks without depending
on any human cooperation, e.g., no one need remember to manually
hit a load or dump switch to signal the central computer. Because
the system is fully automated, it is highly reliable. In addition,
the data gathered by real-time radio data downloading from the
on-board weighing device, when stored and analyzed by the central
computer, allows precise control of the routing of the trucks for
top efficiency.
Referring to FIG. 19b, by way of transceiver 150 the trucks 11
download a data frame comprising a synchronization word followed by
the truck number and data representative of a truck condition,
e.g., a load or dump condition. In response to this received data
from the trucks 11, the central computer stores and analyzes this
data. After the central computer properly analyzes this data it
may, depending on truck status, send a data frame comprising a
synchronization word followed by the particular truck and loader
numbers. In order to prevent simultaneous or overlapping
transmissions from the trucks 11, the trucks 11 transmit in
response to an inquiry signal from the central computer 155. The
central computer 155 polls the trucks 11 to determine if any truck
is ready to send data. In response to a polling, the trucks 11
response by transmitting the required data (dump, load or other
data) in the format shown in FIG. 19b.
Keying the transceiver 150 for transmission of the data frame
occurs in response to the sensing of data generation such as a dump
condition (activation of the dump switch 137) a load condition
(sensing of a first bucket) and the like. Obviously, whether the
data frame includes load or dump data indications depends on
whether the dump switch 137 has been activated or whether a first
bucket has been added. As will be explained in greater detail in
connection with FIGS. 20a-b, the central computer 155 receives the
data in the data frame from the trucks 11 and concludes from the
data which loader 160 can provide the quickest load cycle time for
a truck now dumping and therefore ending its previous load cycle or
which dump site is the proper one for a truck now loading and
therefore ready for instructions and/or directions to a dump site.
Once the central computer 155 has determined which loader will
minimize the time of a load cycle or which dump site is the proper
one, the computer transmits by way of transceiver 155a the data
frame containing a particular truck number the computer wishes to
address and a particular loader or dump site number which the
computer wishes to direct the truck. Each truck receives the data
frame from the central computer 155, but only the truck having the
same number as the number transmitted with respond to the data
containing the loader number. When the truck number and the truck
number data correspond, the loader dump site or other site
designation number transmitted with the truck number is either
displayed on the LED display 117 of the designated truck or printed
as hard copy on the truck's printer 119. From the loader number,
the truck operator knows which loader to go to for his next load.
By analogy, the central computer 155 may also deliver destination
data when multiple dump sites are used or a rest stop designation
if the operator is scheduled for a break. Many other useful
destinations will be appreciated by those familiar with mining
operations.
Referring briefly to FIG. 19c, an opening 1300 may be provided in
the floor of the body 13 for allowing a switch assembly to sense
the presence of a load and thereby indicate to the sensor
processing unit 101 when loading begins. Such a device could
combine with the sensor processing unit 101 to give a simplified
truck dispatch system according to FIG. 19a. With the addition of
the switch assembly of FIG. 19c, the on-board weighing device and
its complementary load sensors (except the dump sensor) are not
required for simply dispatching trucks in response to load and dump
signals only.
The opening 1300 in the floor of the truck body 13 is covered by a
flexible, but rugged material 1301 such as a thick rubber mat which
is secured to the bed of the truck body along its perimeter. A
hinged flap 1302 is biased upwardly by a spring and shaft assembly
1303. In response to the introduction of material into the truck
body 13, the flap 1302 closes over the opening 1300 and pushes down
the plunger of a switch 1304. Of course, the switch closure
generates a signal indicative to the sensor processing unit 101 of
the starting of loading.
In the flowchart of FIG. 20a, the data received from the trucks 11,
is manipulated and stored in order to accurately determine the
correct loader to route a truck when it completes a haul cycle. A
periodic interrupt causes the central computer to execute the steps
of FIG. 20a. At each interrupt, the central computer 155 polls all
the trucks 11 for data. In step 1097, the present time is read and
temporarily stored. In step 1098, the truck number is initialized
to a starting value. The transceiver 155a is keyed in step 1099 and
a formated inquiry signal is sent to the designated truck. If data
is detected in step 1100, the computer reads the data and
manipulates it in accordance with steps 1110-1190; otherwise, the
truck number is incremented in step 1102, and a new truck is polled
for data in step 1099. If all the trucks have been pooled for this
interrupt, step 1104 returns the central computer 155 to the main
program. When a valid transmission is detected, the flowchart moves
to step 1110 where the truck number is decoded. If the received
data frame includes a dump indication, the most recent load time
for this particular truck is subtracted from the current time to
provide a loaded haul time in step 1140. If a dump indication is
not present, the program branches to step 1132 where the data frame
is checked for a load indication. If the data frame includes a load
indication, the program branches from step 1132 to step 1135
wherein the real time is stored as the "load time". If a load
indication is not present, step 1132 returns the central computer
155 to the main program. By analogy, other downloaded data
(gearshift, operator number change, etc.), may be identified by the
central computer 155 and routed to appropriate storage locations at
the central computer. Of course, data of different types (e.g.,
elapsed times, weights of buckets, etc.) must be encoded in a
conventional manner by the sensor processing unit 101 in order that
the central computer 155 can identify the data for
categorization.
At the central computer 155, a data base (not shown) is maintained
for each truck as well as for each model of truck. For example, in
a fleet of 20 trucks, trucks one through 10 may be a first type of
truck with a particular capacity, while trucks 11-20 may be a
second type of truck with a different capacity. From the makeup of
the truck fleet, a data base is organized to best provide useful
information. For the above-mentioned fleet of 20, the data base is
divided into two main sections, one for each type of truck, and
each section has ten cells, one for each truck. By organizing the
data base in the foregoing manner, data for each truck can be
collected and manipulated and, also, data for each type of truck
can be obtained. In addition, since each haul cycle for a truck is
identifiable with a particular loader, a data base is also set up
for each truck/dump site/loader combination.
In the data base at the central computer 155, the cell for each
truck includes data identifying the last loader to which the truck
was directed and the time it was directed. Therefore, an average
loaded haul time for a particular truck hauling from a particular
loader to a particular dump site can be determined. In step 1150,
an average haul time for each of the trucks from each of the
loaders to each dump site, stored in an array in RAM 155d, is
accessed. The most recent haul time for a particular loaded truck,
a particular loader and a particular dump site is added to the
average in order to update it in step 1160. The updated average
loaded haul time is returned to the storage array in step 1170.
Because the central computer 155 is in communication with each of
the trucks 11, it knows the number of trucks 11 that have been sent
to a particular loader; it also knows how many of those trucks sent
to a particular loader 160 have indicated loading has begun. From
the foregoing information, as the trucks 11 become available from a
dump site or other areas, the central computer 155 executes an
algorithm in step 1180 to determine which loader can most quickly
load the current truck and return it to the dump site. The central
computer 155 calculates a "delay" time for each loader and
identifies the loader with the minimum delay as the truck's
destination. For each loader 160 the delay may be determined as
follows: ##EQU7##
From the foregoing algorithm, the central computer 155 calculates
in a conventional manner from available data the number of trucks
in transit to or at the loader (n). A calculation of the number of
trucks at the loader site or in transit thereto is easily derived
from available data since the central computer 155 identifies which
trucks have been directed to a given loader 160 and have not yet
transmitted a load start signal. The load time of each loader is
calculated from data made available by the truck's sensor
processing unit 101. The beginning of the load is marked by the
central computer 155 when it receives a load signal from the sensor
processing unit 101. The end of the loading is marked by the
central computer 155 when it receives the first gear shift signal
sensed by the sensor processing unit 101 from the gear sensor 135
after transmission of the load start signal to the central computer
155. Obviously, for the central computer 155 to calculate a load
time and an average load time for each loader, the on-board
weighing device must transmit both the load start signal and a
signal indicative of the first gear change. The latter signal is
not set forth in the flowchart diagrams, but it will be appreciated
by a programmer that the data may be transmitted in response to a
polling request from the central computer 155.
Because the loading is sequential (i.e., each truck 11 is fully
loaded in its turn), only the latest load transmission signal can
be from a truck still being loaded. Therefore, more than one load
transmission signal indicates some trucks are in transit back to
the dump site. Obviously, these trucks need not be considered in
calculating a time delay for loading. In order to accurately
account for the time delay caused by the truck currently being
loaded, the time difference between the last load signal and the
average load time should be subtracted from the product of the
number of trucks at or in transit to the loader and the average
load time. To this difference is added the travel time for the
truck being directed from that truck's present location (normally a
dump area) to the particular loader 160. For example, two loaders
may have load delays of five minutes and ten minutes, respectively,
before considering truck travel time. However, if the travel time
to the first loader 160 is 12 minutes while the second loader has a
five minute travel time, this travel time is subtracted from the
time delay to arrive at a total delay time which is -7 minutes for
the first loader and +5 minutes for the second loader; thus, the
central computer 155 designates the first loader as the truck's
destination since the minus delay time indicates the time the
loader will be waiting for a truck. After the delay of each loader
160 is calculated, the central computer 155 transmits a signal at
step 1190 having data identifying the particular truck for which
the transmission is intended and also having data indicating the
particular loader number with the current minimum delay time.
In response to the transmissio from the central computer 155, the
transceivers 150 of all the trucks 11 lock onto the signal during
the sync portion of the transmission and compare the transmitted
truck number to their own numbers. FIG. 20b illustrates the
flowchart to execute the comparison of a transmitted truck number
and the stored truck number. In a simple scheme, the steps of FIG.
20b are executed periodically by a timer interrupt. At each
interrupt, the CPU 103 of FIG. 16 checks to see if the transceiver
150 is receiving a transmission. If no signal is present in step
1210, the program returns the CPU 103 to the main program. If a
signal is present, the transmitted truck number is captured and
compared to the truck's own number at step 1220. If they are not
identical, the data identifying a particular loader number, dump
site or designated site, which follows the transmitted truck
number, is ignored. When a match occurs between truck numbers, the
central computer 155 is contacting a particular truck 11 either to
poll it or to instruct it which loader 160, dump site 161 or
designated site to go to. In order for the sensor processing unit
101 to know which instruction is currently being received, step
1225 determines if the data following the truck number is a polling
request. If it is a polling request, the program determines at step
1240 if ARRAY VII contains data for downloading; if it does, the
transceiver 150 is keyed and the appropriate data (e.g., dump, load
gearshift, operator number change, etc.) is transmitted to the
central computer 155 in step 1250. Alternatively, if the received
data is not a polling inquiry, it must be instructions for a
loader, dump site or other destination. Therefore, the loader
number, dump site or other designation is stored and displayed to
the truck operator at step 1260.
In a haul cycle there are two important travel segments--the loader
to dump site segment and the dump site to loader segment. These two
segments are the main components of a full cycle. Because the
on-board weighing device detects when loading begins and when
dumping occurs, important data can be transferred at those times
from the truck 11 to the central computer 155 for processing when
the truck is polled. For example, the ton.mile calculation by the
sensor processing unit 101 is important for each haul segment since
it indicates a degree of tire use for the haul segment. This data
may be transmitted to the central processor 155 for processing in
response to polling of the trucks. Management personnel can monitor
(the central computer 155 may, alternatively, include a software
routine to monitor this or other data) the updated or averaged
ton.mile data from each haul segment at the site of the central
computer 155 in order to dispatch trucks in a manner to ensure even
fleet accumulation of ton.mile and/or ensure tires are not being
used above their rated ton.mile per hour rating. Of course, other
data available from the on-board weighing device can be downloaded
to the central computer 155 in the same manner as the foregoing
data. Finally, a portion of the data downloaded to the central
computer 155 may, in addition, be downloaded to a processor (not
shown) on-board the loader 160 loading the truck in order to give
the operator of the loader an indication of the truck's load
condition. Such a communication link would be similar to the link
set forth above in connection with the central computer 155. The
specific type of radio link could be any type of commercially
available data link suitable for transfer of the type of data here
involved such as REPCO, Inc., RF modem, RDS-1200, 944-960 MH.sub.z,
full duplex. It will be appreciated from the foregoing that data
such as the operator summaries of ARRAY II will be downloaded from
the memory of the sensor processing unit 101 to the central
computer 155 for storage and analysis.
In order to reduce the expense of providing high-power transceivers
on each truck 11, for data downloading stationary repeaters 160a
and 161 (in FIG. 19a) are provided at scattered locations in the
working site. By providing these repeaters 160a and 161, each
transceiver 150 need be only a low power device. In addition, by
methods well known in the field of communications, the central
computer 155 may identify which repeater 160a and 161 is
retransmitting the downloading of truck data. By knowing the
particular repeater 160a and 161 in which a truck 11 is in range,
the central computer 155 may track movement of the trucks.
Moreover, during data download polling of the trucks 11 by the
central computer 155, data may be transmitted indicating an
"out-of-service" condition or an "in-transit" condition for the
truck. By providing data such as the foregoing, the central
computer 155 may keep track of which trucks are currently loading,
dumping, in transit or out of service. As trucks 11 are directed to
various loaders 160, dump sites, etc., the central computer 155
notes a projected time of arrival for the truck based on its
historical data base. If a truck 11 fails to arrive at its
designated location within this time period plus a predetermined
percentage of the period, then the central computer 155 will
provide a sensory alert ot management personnel so that the status
of the truck can be checked. For thos trucks 11 which go out of
service, the central computer 155 can update the load delay for the
particular loader 160 for which the out-of-service truck was
destined.
As an extension of the foregoing data downloading and controlling
of truck movement, the interaction of the sensor processing units
101 of the trucks 11 and the central computer 155 also provides the
ability for data file management at a remote location.
Specifically, information from each of the sensor units 101 is
downloaded to a master data file associated with the central
computer 155 where the data may be manipulated in order to provide
useful real time information to management personnel. For example,
from real time data the central computer 155 may analyze the
average number of loads or tons loaded per hour by a particular
loader 160 and/or average number of loads or tons hauled by a
particular truck. From the foregoing analysis, accurate projections
for the best utilization of the trucks and loaders can be
developed.
In addition to receiving the downloaded data and dispatching trucks
11 to proper loaders 160, dump sites or designated sites, the
central computer 155 maintains data on tonnage loaded by particular
loaders, tonnage hauled by particular trucks and total tonnage
hauled to each dumping area. The central computer 155 records the
out-of-service times for all truck 11 and loaders 160 and
identifies the trucks and loaders which are out of service for the
longest times in a predetermined time period.
Mine management with this system can see what has been done in
terms of mine production and can make extremely accurate
projections, 1 month, 6 months, possibly even 12 months down the
road. With these projections as to what total mine production can
be, e.g., anticipated tons of various material to be moved, the
mine operating personnel can make equipment assignments and changes
to those equipment assignments so that mine production does, in
fact, meet mine production projections.
For example, the central computer 155 cumulatively records ton-mile
per hour data over a given time frame so that as a truck
accumulates ton-mile per hour figures the cumulative figures for
all trucks are compared and the trucks with excessive ton-mile per
hour numbers can be dispatched to locations from which less
ton-mile per hour figures occur.
Additionally, the central computer 155 as well as the sensor
processing units 101 may analyze vehicle component strain, such as
engine operating temperature, hydraulic oil temperature, heat
buildup in the tires, etc. As a particular component on a vehicle
approaches a preset limit, the vehicle may on future haul
dispatches be dispatched to a haul that might be less trying on the
vehicle, i.e., for a mine with a multi-bench operation vehicles may
be rotated so that no one vehicle is continually hauling off of the
lowest bench. This analyzation of vehicle component strain
obviously turns on the need to add additional vehicle monitors to
the vehicle and provide radio downloading transmission capabilities
from these monitors to the central computer 155.
Conceptually, the master data file (not shown) of the central
computer 155 contains four primary files from downloading data:
(1) Loading time for each truck with each piece of loading
equipment;
(2) Loaded haul time for each loader to each dump area for each
truck;
(3) Empty return time from each dump area to each loader for each
truck; and
(4) Total haul cycle time for each truck from each loader to each
dump area. This master data file may be either separate from or
incorporated with the data base for each type of truck (having
subfiles for each truck) and for each loader/dump site
combination.
Each of the four primary files of the master data file is separated
by loading equipment type, truck type and dump site, e.g., make,
model, size, type of body or type of material to be hauled, whether
it is ore, overburden, dual purpose, etc. For example, data for 170
ton trucks are filed separate from data for 120 ton trucks. Each
class of truck, loader and dump site combination has a separate
historical subfile to be used to determine how long it should take
a truck of that class to get from a dump to loading site or vis
versa. With respect fo the loaders 160, a similar subfile system
exists for each class. In addition, loader 160 has a subfile for
each type of truck it loads. These subfiles store historical data
on how long it takes the loaders 160 to load any particular type of
truck 11.
As a particular example of the data base and master data file, if a
mine had 10-170 ton Wabco trucks and 10-120 ton Euclid trucks, then
the central computer 155 would have a data base comprising a
historical subfile for each truck, loader/dump site combination,
i.e, 20 truck subfiles. Data from the 10 Wabco subfiles is averaged
together to comprise a master Wabco data file; likewise, a master
Euclid data file is created for the Euclid trucks. Then, as each
respective truck generates data, its corresponding historical
subfile is updated and averaged according to that data. In response
to downloading data for updating of these historical subfiles for
each truck, the four primary files of the master data file for the
truck class (e.g., Euclid or Wabco) are also updated.
As evidenced by the degree and variety of data available from the
on-board weighing devices, the downloading communications link
between trucks 11 and the central computer 155 is potentially much
more than a RF data downloading link, it is also the means for a
traffic controller. Downloading of all or selected portions of data
generated by the sensor processing unit 101, allows the central
computer 155 to function as a mine management system. The following
description of the functioning of such a system is intended as an
outline of the programming steps made possible by the organization
of memory in the central computer 155 into a data base with
subfiles for each truck/loader combination and primary files for
each class of truck as described herein and the downloading of data
in addition to load and dump data as previously discussed in
connection with FIGS. 19a-b and 20a-b.
In order for polling by the central computer to occur sufficiently
often so that the downloading of data may approach a real time data
read out, repeaters 161 should be of sufficient number in strategic
positions. In addition, by identifying their location in the
repeated signal, the repeaters 160a and 161, identify truck
locations, i.e. the data signal from the trucks 11 when received by
the repeater is supplemented with data identifying the repeater. As
data accumulates in each of the sensor processing units 101 of the
trucks 11, it is stored in memory until the truck is within range
of a repeater 160a or 161, whereupon the data is downloaded to that
repeater and sent on to the central computer 155. With
strategically placed repeaters 161, not only is the data downloaded
at close to a real time basis, but the repeaters keep an accurate
track of truck location.
For example, as a truck 11 leaves the dump area 1, it is notified
by the central computer 155 via the repeater 161 at dump area 1
which loader 160 had the minimum delay. The truck 11 is then on its
way to that particular loader location. The truck 11 possibly
accumulates some data in route to that particular loader 160a. As
it comes within range of the particular loader 160a, data
accumulated enroute from dump area 1, if not previously
transmitted, is transmitted to the repeater 160a on the loader and
resent to the central computer 155, thus identifying the truck's
current vicinity.
As soon as the central computer 155 detects data downloading from
the truck through the repeater 160a at the loader location to which
the truck was dispatched, it knows that the truck has arrived in
the vicinity of the particular loader. If in route to the
designated loader, the truck 11 passes another loader 160 or comes
within the range of another strategically placed repeater 161
(possibly dump area 2 in FIG. 19a), any data accumulated is
downloaded via that repeater 161 to the central computer 155,
thereby again identifying truck location.
Once the truck 11 gets to its designated loader 160 or loading
area, the gearshift is placed in neutral or reverse by the driver.
This change in gear is detected by the gear sensor 135 of the
on-board weighing device and the data is downloaded via the
repeater 160a to the central computer 155, and the central computer
thereby has further confirmation that the truck 11 has arrived at
the designated loader. It should be noted, however, that if there
are two or more loders in the same immediate vicinity or within the
transmit range of the radio signal of the truck, these loaders
should be classed as one loading area or one piece of loading
equipment for purposes of data handling by the central computer
155.
With the truck 11 in the general area of the designated loader 160,
as the truck positions itself for loading (i.e., shifts foward,
reverse, etc.), data is generated that is downloaded via the
repeater 160a to the central computer 155 and, with the first
bucket pass into the truck, additional data is generated that is
downloaded to the central computer 155. With the first bucket pass,
the central computer 155 looks at one of the primary files in the
master data file for the average loading time of this particular
loader 160 for loading this particular type of truck 11. Based on
this primary file, the central computer 155 determines when this
truck 11 will be fully loaded and when the next truck is needed at
this particular loader 160 for continuous truck loading to
occur.
With the last bucket pass into the truck 11, (sensed by a gear
shift forward leaving the loading area) this data is downloaded to
the central computer 155 which accesses another primary data file
from the master data file; this file contains the average travel or
haul time of this particular type of truck from this loading
location to various dump areas that this truck can be directed to.
The central computer 155 then analyzes the projected truck arrival
time at each of these areas based on its record of trucks already
enroute to the dump areas and determines which dump area will have
the least congestion. The central computer 155 then analyzes trucks
enroute and their projected arrival times to direct the truck just
loaded to a particular dump area as designated by the central
computer as well as determining what the elapsed time should
approximate from this final bucket pass (i.e., gear shift forward)
until the truck arrives at the designated dumping area. As the
truck 11 leaves the area of the loader 160 for the dump area, data
(such as gear shifting, distance traveled, etc.) accumulates and is
transmitted from the truck via the repeater 160a on the loader to
the central computer 155, and the central computer 155 estimates
when this truck will arrive at its designated dump area.
Upon coming within range of the designated dump area, the repeater
161 receives any data accumulated by the truck 11 and downloads it
to the central computer 155. With the travel time of the truck 11
from the loading area to the dump area noted by the central
computer 155, the appropriate primary file of the master data file
is updated. (Loaded travel time is the time from the first forward
gear shift after loading commences until the dump switch is
activated.) As the truck dumps, the dump switch is activated and
data indicative of this is generated by the sensor processing unit
101. This data is downloaded to the central computer 155 and, at
this point, the truck 11 is then available for another load.
Therefore, the central computer 155 searches to determine with what
loaders 160 this particular type of truck is being used. (The
central computer 155 differentiates between trucks of different
load types-different body styles; for example, trucks hauling coal
or overburden in a mining operation.) The central computer 155
reviews the loading/haulage status of each loader 160 and, it
analyzes when each loader will need another truck to load based on
(1) the historical loading data files, (2) what trucks 11 have
already been dispatched to each of the loaders 160 and (3) the
historical empty travel time from the particular location of the
truck 11. The central computer 155 then reviews the primary travel
time file from the dump area (the truck's particular location) to
each particular loading area. From the travel time data, the
central computer 155 looks at the historical empty return truck
time and determines which loader will need a truck the soonest and,
in response to this determination, transmits directions and
instructions to the truck dispatching it to the particular
loader.
At the same time that loader destination information is transmitted
to a truck 11, the central computer 155 reviews a historical data
file of total haul cycle time for that truck from the loader to
which the truck has been dispatched and identifies a median haul
cycle time to all possible truck dump locations. A percentage of
the median time is added to the median in order to provide a time
period within which the truck should be expected to complete a haul
cycle i.e., dumping another load. For example, if the median haul
cycle were 12 minutes and the central computer 155 is programmed to
add 20% to this time, if dump data were not registered as being
downloaded from this truck within this 12 minutes+20%, the central
computer then would flash to its operator that the truck in
question is late in completing its haul cycle to a dump area;
whereupon, the operator of the central computer 155 may via
conventional two-way radio the truck's driver to see if there is a
problem with the truck.
If a truck driver parks the truck for a break or a rest stop, the
driver alerts the operator of the central computer 155 to that fact
via conventional two-way radio. In response to this received data,
the operator of the central computer 155 punches up that truck
number and indicates that truck's location and that no loads will
be hauled for a predetermined time period and that possibly no data
transmissions will be occuring over this same time period. (Trucks
should only be parked within range of repeater 160a or 161). In
some cases it is possible to communicate the same information via
data downloaded through an interrupt instituted by the operator's
selection of an appropriate key of the keyboard 122.
When a truck goes out of service because of a breakdown, operator
rest or the like, the central computer 155 dispatches new available
trucks to the loading area previously transmitted to the parked (on
break) truck and then transmits to the parked truck a new updated
loading location. This procedure is repeated until the parked (on
break) truck is indicated as being back in service by data
indicating such things as the shifting of gears. If the truck was
loaded when parked, no dispatching may occur since the central
computer 155 recognizes the truck is loaded and must be first
dumped before it can be dispatched.
If no data has been received, at the end of the time period
selected by the truck operator as his break time or down time, the
central computer 155 will flash the truck number to the operator of
the central computer. The central computer operator may radio, via
conventional two-way radio, the truck to check on the truck's
status. If the central operator finds the truck is still down for
whatever reason, he may punch up the truck number and indicate how
many more minutes the truck will be down. This process continues to
be repeated by the central computer 155 until the truck is back in
service or temporarily taken out of service.
With respect to truck travel from the dump area to a loader, the
central computer 155 records the time of truck dispatch and looks
for that truck to arrive at the designated loading area within a
predetermined time based on historical truck return time in a
primary data file. If the truck is late in arriving at its
designated loading area, i.e., no data downloading to indicate
arrival, the truck number is flashed to the operator of the central
computer whereupon he may radio, via conventional two-way radio,
the truck driver to check on that truck's status.
The central computer 155 also follows the foregoing steps when it
detects a truck leaving a loading area headed for a designated dump
area. The central computer 155 identifies in its data file the
average haul travel time it takes a like truck to get to the
designated dumping area. If further data is not detected by the
central computer 155 within this average time, then that truck
number is flashed to the operator of the central computer whereupon
he may check on that truck's status.
In addition to receiving downloaded data, monitoring and
dispatching trucks 11 in the foregoing manner, the central computer
155 also identifies and monitors the various loaders 160 by
identifying the repeater 160a through which truck data is coming to
the central computer. Accordingly, the central computer 155, as
data is downloaded to it, analyzes the average number of loads
and/or tons loaded per hour by a particular loader 160 and how many
minutes occur between each load. As the central computer 155
monitors each loader 160 through data downloading, if it detects a
lack of load information coming from a particular repeater source,
it flashes to the operator of the central computer the number of
that repeater source (or loader). The operator of the central
computer 155 may radio, via conventional two-way radio to the
loader operator and identify whether there is a problem with the
loader. If that particular loader 160 is down, the loader operator
may respond to the operator of the central computer 155 with an
estimate of how long he will be down. The operator of the central
control computer 155 then enters into the central computer that
this loader will be down for a particular time period.
The central computer 155 adds a percentage of this particular time
period to the estimated time period in order to provide a buffer
range. At the end of this increased time period, the central
computer 155 checks the downloaded status of loader 160 and
determines whether loading data is present. If no loading data is
present from this loader, the loader number is again flashed to the
operator of the central control computer 155 whereupon he may again
check with the operator of that loader to see how much longer it
will be down. This additional time is entered into the central
computer 155 and the steps are repeated.
As soon as data is entered by the operator of the central computer
155 indicating that a particular loader 160 is down, the central
computer redispatches trucks 11 away from this loader with any
trucks in the immediate vicinity of that loader getting their
signal through the repeater 160a on this loader while trucks in
route may possibly have to arrive in the vicinity of the loader
before picking up a redispatch number. For redispatching, the
central computer 155 does not consider specific travel times;
rather, by way of simplification, it sets all travel times equal
for the loading locations to which the trucks are redispatched.
This eliminates any data errors redispatching might otherwise
cause.
As a piece of loading equipment is down the time when that piece of
loading equipment is supposed to be back up is automatically
registered in the central computer 155 and the central computer,
depending on programming, can automatically dispatch one and only
one vehicle, or if so programmed 2 or more trucks, to that piece of
loading equipment. Or, if so programmed, the central computer 155
can flash the respective number of the piece of loading equipment
to the central computer operator, whereupon he asks, via
conventional two-way radio, the loading equipment operator whether
that piece of loading equipment is again up and ready to run so
that trucks can be dispatched to it. If the answer is yes, trucks
can be dispatched to that piece of loading equipment, the operator
of the central computer 155 enters in on his keyboard that, that
particular piece of loading equipment is again up and running. The
central computer 155 then immediately takes over automatic
dispatching and dispatches the first available truck to that piece
of loading equipment.
If the central computer 155, through data being downloaded to it,
determines there is either excess haulage capacity or loading
capacity, it signals the computer operator. If excess haulage
capacity is indicated, the computer 155 indicates which truck 11 is
closest to a required preventive maintenance period. A similar
determination is made for the loaders 160 when excess loading
capacity is indicated. As soon as the excess truck 11 or loader 160
is identified and maintenance personnel are available, the central
computer 155 dispatches the identified truck or loader to the
maintenance shop for preventive maintenance work and/or notifies
maintenance personnel to work on the loader 160.
With reference to equipment maintenance, if so desired by mine
management, equipment maintenance can be incorporated with the
sensor processing unit 101 and the central computer 155 data
downloaded so that as equipment maintenance occurs, equipment
maintenance costs can be accurately tracked, since the sensor
processing unit 101 and the central computer 155, via data
downloading, will be tracking amount of equipment operating time,
it will conversely be tracking equipment down time. As down time
occurs, through the proper use of the operator number function of
the sensor processing unit 101 and data downloading from this unit
to a central computer 155 with the operator number function, it is
possible to identify why a piece of equipment is down and through
the proper use of operator number codes as well as when a piece of
equipment goes back into service, and as this data is generated for
downloading to the central computer 155 via the operator number
code on keypad 122, the cost of all parts and supplies used during
the time that the truck is out of service can be entered directly
into the central computer 155 via the operator of the central
computer, i.e., a truck is down for transmission repair. The code
for transmission repair is entered, via the operator number code on
keypad 122 into the sensor processing unit 101 for data
downloading, when the truck goes back into service, the cost of
parts and supplies to repair the transmission is entered into the
central computer via the operator of the computer. If, however, the
actual cost of the transmission repairs is not immediately known as
a truck goes back into service, when they do become known, the
operator of the central computer 155 can still enter the cost of
parts and supplies, what they were for, and during what time period
they were incurred so that the central computer can go back and
allocate for each period of equipment down time as identified from
data downloaded from sensor processing unit 101, the cost of repair
parts and supplies associated with that segment of equipment down
time.
From the foregoing it will be appreciated that the on-board
weighing device provides the sensor processing unit 101 with raw
data that can be downloaded to a central computer for storage and
analysis and then be refined to provide indications of truck and
operator efficiency. By analyzing various mining parameters based
on this downloaded raw data, the truck performance can be improved,
thereby reducing the substantial cost of operating off-road, heavy
duty trucks.
* * * * *